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  • 101.
    Enman, Josefine
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Rova, Ulrika
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Raman analysis of synthetic eritadenine2008Inngår i: Journal of Raman Spectroscopy, ISSN 0377-0486, E-ISSN 1097-4555, Vol. 39, nr 10, s. 1464-1468Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Eritadenine, 2(R),3(R)-dihydroxy-4-(9-adenyl)-butyric acid, is a cholesterol-reducing compound naturally occurring in the shitake mushroom (Lentinus edodes). To identify the unknown Raman spectrum of this compound, pure synthetic eritadenine was examined and the vibrational modes were assigned by following the synthesis pathway. This was accomplished by comparing the known spectra of the starting compounds adenine and D-ribose with the spectra of a synthesis intermediate, methyl 5-(6-Aminopurin-9H-9-yl)-2,3-O-isopropylidene-5-deoxy-β-D-ribofuranoside (MAIR) and eritadenine. In the Raman spectrum of eritadenine, a distinctive vibrational mode at 773 cm-1 was detected and ascribed to vibrations in the carbon chain, ν(C--C). A Raman line that arose at 1212 cm-1, both in the Raman spectrum of MAIR and eritadenine, was also assigned to ν(C--C). Additional Raman lines detected at 1526 and at 1583 cm-1 in the Raman spectrum of MAIR and eritadenine were assigned to ν(N--C) and a deformation of the purine ring structure. In these cases the vibrational modes are due to the linkage between adenine and the ribofuranoside moiety for MAIR, and between adenine and the carbon chain for eritadenine. This link is also the cause for the disappearance of adenine specific Raman lines in the spectrum of both MAIR and eritadenine. Several vibrations observed in the spectrum of D-ribose were not observed in the Raman spectrum of eritadenine due to the absence of the ribose ring structure. In the Raman spectrum of MAIR some of the D-ribose specific Raman lines disappeared due to the introduction of methyl and isopropylidene moieties to the ribose unit. With the approach presented in this study the so far unknown Raman spectrum of eritadenine could be successfully identified and is presented here for the first time.

  • 102.
    Enman, Josefine
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Rova, Ulrika
    Berglund, Kris A.
    Quantification of the bioactive compound eritadenine in selected strains of shiitake mushroom (Lentinus edodes)2007Inngår i: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 55, nr 4, s. 1177-1180Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cardiovascular disease is one of the most common causes of death in the Western world, and a high level of blood cholesterol is considered a risk factor. The edible fungus, shiitake mushroom (Lentinus edodes), contains the hypocholesterolemic agent eritadenine, 2(R),3(R)-dihydroxy-4-(9-adenyl)-butyric acid. This study was conducted to quantify the amount of the cholesterol reducing agent eritadenine in shiitake mushrooms, in search of a potential natural medicine against blood cholesterol. The amounts of eritadenine in the fruit bodies of four different shiitake mushrooms, Le-1, Le-2, Le-A, and Le-B, were investigated in this study. To achieve this goal, methanol extraction was used to recover as much as possible of the hypocholesterolemic agent from the fungal cells. In addition, enzymes that degrade the fungal cell walls were also used to elucidate if the extraction could be further enhanced. To analyze the target compound, a reliable and reproducible HPLC method for separation, identification, and quantification of eritadenine was developed. The shiitake strains under investigation exhibit up to 10 times higher levels of eritadenine than previously reported for other shiitake strains. Further, pretreating the mushrooms with hydrolytic enzymes before methanol extraction resulted in an insignificant increase in the amount of eritadenine released. These results indicate the potential for delivery of therapeutic amounts of eritadenine from the ingestion of extracts or dried concentrates of shiitake mushroom strains.

  • 103.
    Faisal, Abrar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Holmlund, Mattias
    Swedish University of Agriculture Sciences.
    Ginesy, Mireille
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Holmgren, Allan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Enman, Josefine
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Grahn, Mattias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Recovery of l-Arginine from Model Solutions and Fermentation Broth Using Zeolite-Y Adsorbent2019Inngår i: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 7, nr 9, s. 8900-8907Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Arginine was produced via fermentation of sugars using the engineered microorganism Escherichia coli. Zeolite-Y adsorbents in the form of powder and extrudates were used to recover arginine from both a real fermentation broth and aqueous model solutions. An adsorption isotherm was determined using model solutions and zeolite-Y powder. The saturation loading was determined to be 0.2 g/g using the Sips model. Arginine adsorbed from a real fermentation broth using either zeolite-Y powder or extrudates both showed a maximum loading of 0.15 g/g at pH 11. This adsorbed loading is very close to the corresponding value obtained from the model solution showing that under the experimental conditions the presence of additional components in the broth did not have a significant effect on the adsorption of arginine. Furthermore, a breakthrough curve was determined for extrudates using a 1 wt % arginine model solution. The selectivity for arginine over ammonia and alanine from the real fermentation broth at pH 11 was 1.9 and 8.3, respectively, for powder, and 1.0, and 4.1, respectively, for extrudates. To the best of our knowledge, this is the first time recovery of arginine from real fermentation broths using any type of adsorbent has been reported.

  • 104.
    Faisal, Abrar
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Zarebska, Agata
    Saremi, Pardis
    Korelskiy, Danil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Ohlin, Lindsay
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Grahn, Mattias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    MFI zeolite as adsorbent for selective recovery of hydrocarbons from ABE fermentation broths2014Inngår i: Adsorption, ISSN 0929-5607, E-ISSN 1572-8757, Vol. 20, nr 2-3, s. 465-470Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    1-Butanol and butyric acid are two interesting compounds that may be produced by acetone, butanol, and ethanol fermentation using e.g. Clostridium acetobutylicum. The main drawback, restricting the commercialization potential of this process, is the toxicity of butanol for the cell culture resulting in low concentrations of this compound in the broth. To make this process economically viable, an efficient recovery process has to be developed. In this work, a hydrophobic MFI type zeolite with high silica to alumina ratio was evaluated as adsorbent for the recovery of butanol and butyric acid from model solutions. Dual component adsorption experiments revealed that both butanol and butyric acid showed a high affinity for the hydrophobic MFI zeolite when adsorbed from aqueous model solutions. Multicomponent adsorption experiments using model solutions, mimicking real fermentation broths, revealed that the adsorbent was very selective to the target compounds. Further, the adsorption of butyric and acetic acid was found to be pH dependent with high adsorption below, and low adsorption above, the respective pKa values of the acids. Thermal desorption of butanol from MFI type zeolite was also studied and a suitable desorption temperature was identified.

  • 105.
    Falcon, Javier A.
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Monitoring of antisolvent addition crystallization with Raman spectroscopy2003Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 3, nr 6, s. 947-952Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fiber optic Raman spectroscopy was used for in situ monitoring of antisolvent addition crystallization of cortisone acetate. Raman spectral features of the solvent, the antisolvent, and the solute were monitored to measure the relative concentration of the components. Different rates of antisolvent addition were monitored and the resulting solid-state form was characterized using Raman spectroscopy and DSC. Raman spectroscopy was used to monitor dehydration during storage of the product crystals. The current study demonstrates the advantages of using Raman spectroscopy to monitor the solution phase during crystallization and simultaneously monitoring the solid-state form.

  • 106.
    Feng, Lili
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    ATR-FTIR for determining optimal cooling curves for batch crystallization of succinic acid2002Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 2, nr 5, s. 449-452Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The temperature profile applied during batch cooling crystallization affects the supersaturation level, which in turn affects the crystal size distribution. It is possible, in principle, to calculate the optimal cooling profile; however, the nucleation and growth kinetics are rarely known to the degree of accuracy necessary for this calculation. The current study demonstrates an alternative approach to determination of the optimal cooling profile without any prior knowledge of kinetic data or subsequent modeling. An attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometer was used to monitor the supersaturation level during batch cooling crystallization. The ATR-FTIR was interfaced to a LABMAX automatic reactor system that was used in a feedback mode to control the cooling rate so that the supersaturation level remained close to the solubility throughout the cooling process. The resulting temperature profile corresponds to the optimal operating conditions for the maximum in the mean crystal size.

  • 107.
    Filatov, D.
    et al.
    Umeå universitet.
    Ingemarson, R.
    Umeå universitet.
    Johansson, E.
    Umeå universitet.
    Rova, Ulrika
    Thelander, L.
    Umeå universitet.
    Mouse ribonucleotide reductase: from genes to proteins1995Inngår i: Biochemical Society Transactions, ISSN 0300-5127, E-ISSN 1470-8752, Vol. 23, nr 4, s. 903-905Artikkel i tidsskrift (Fagfellevurdert)
  • 108.
    Gerlach, Inga
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska fakulteten.
    Operator Training Simulators towards Industrial Biotechnology2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Biotechnological processes are carried out by applying advanced and demanding process strategies. Thus, fundamental understanding and knowledge about the applied microorganism is required to achieve high productivity and profitability. Therefore, computer-based simulation has been integrated into training methodologies for supplementing and expanding academic education and industrial operator training, in order to provide more effective as well as cost- and time-efficient training.

    Operator training simulators (OTS) are computer-based training tools that represent the real laboratory or plant within an interactive, virtual environment. Trainees can learn about cause-and-effect relationships during the virtual process to improve process understanding. Also, trainees and operators get the opportunity to develop, maintain and improve their operational skills. The virtual environment allows delayed operational actions and operational faults, as they are not interfering with the real process. Acceleration of the simulation speed makes training more effective. For instance, different procedures such as start-up and shut-down can be trained in a limited period of training time. Incident and trouble-shooting training can be realized in a safe, virtual environment without exposing the operator to potential risks. So far, OTS are mainly used in military, aviation, medicine and chemical industries. However, there are only a few examples where OTS are applied in biotechnological process applications.

    The aim of this thesis is to expose the benefits of using OTS for biotechnological process applications in academic education and industrial operator training. For this purpose, the feasibility of developing and applying OTS was investigated and discussed. Three OTS for the production of bio-ethanol and recombinant protein production were developed in order to investigate the benefits and their requirements as well as to assess the training effectiveness of these. To visualize the technical system including equipment and distributed control system (DCS), graphical user interfaces (GUIs) were designed, allowing the user to interact with the simulator. Mathematical models were developed and implemented in the OTS to ensure dynamic simulation of the process, where cause-and-effect relationships are realistically described. The essential part of an OTS for biotechnological process applications is the embedded sub-model which describes the biological production system. It is important that the cell growth behaviour within a bioreactor can be  simulated with sufficient accuracy in order to ensure high training effectiveness.

    In the assessment of the training effectiveness in academic education, it was observed that the students’ capability of understanding and controlling complex biotechnological processes improved after OTS training. Students showed better performance in laboratory experiments after participating in OTS pre-training. Moreover, the development of an OTS for an industrial, large-scale bio-ethanol plant illuminates the needs of OTS in biotechnological process industries. It was shown how the conceptual design methodology can be applied in designing an OTS, based on training needs from the industrial user perspective. Also, construction of the OTS including the formulation of mathematical models, the model structure which is embedded in the OTS and the design of the GUIs is covered in this thesis. Whether the use of the OTS will become cost-effective and assure maximum transfer of training depends on long term evaluation. However, application and evaluation of the developed OTS reveal the benefits and training effectiveness of these systems. The findings of the thesis might considerably facilitate the introduction of OTS into academic education and industrial operator training for biotechnological process applications.

  • 109.
    Gerlach, Inga
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska högskolan. University of Applied Sciences, Bremen, Germany.
    Bruening, Simone
    University of Applied Sciences, Bremen, Germany .
    Gustavsson, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska högskolan.
    Mandenius, Carl-Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska högskolan.
    Hass, Volker C.
    University of Applied Sciences Furtwangen, Villingen-Schwenningen, Germany .
    Operator training in recombinant protein production using a structured simulator model2014Inngår i: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 177, s. 53-59Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Model-based operator training simulators ( OTS) could be powerful tools for virtual training of operational procedures and skills of production personnel in recombinant protein processes. The applied model should describe critical events in the bioprocess so accurately that the operators ability to observe and alertly act upon these events is trained with a high degree of efficiency. In this work is shown how this is accomplished in a structured multi-compartment model for the production of a recombinant protein in an Escherichia coli fed-batch process where in particular the induction procedure, the stress effects and overflow metabolism were highlighted. The structured model was applied on the OTS platform that virtually simulated the operational bioreactor procedures in real or accelerated time. Evaluation of training using the model-based OTS showed that trained groups of operators exhibited improved capability compared with the untrained groups when subsequently performing real laboratory scale cultivations. The results suggest that this model-based OTS may provide a valuable resource for enhancing operator skills in large scale recombinant protein manufacturing.

  • 110.
    Gerlach, Inga
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska fakulteten.
    Hass, Volker C.
    Hochschule Furtwangen, University of Applied Sciences Furtwangen, Germany.
    Mandenius, Carl-Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska fakulteten.
    Conceptual Design of an Operator Training Simulator for a Bio-Ethanol Plant2015Inngår i: Processes, ISSN 2227-9717, Vol. 3, nr 3, s. 664-683Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Conceptual design methodology for the configuration and procedural training with an operating training simulator (OTS) in a large-scale plant for commercial bio-ethanol production is described. The aim of the study is to show how the methodology provides a powerful way for finding the best configuration and training structure of the OTS before constructing and implementing the software of the OTS. The OTS principle, i.e., to use a computer-based virtual representation of the real process plant intended for efficient training of process operators, has long since been applied in aviation and process industries for more efficient and flawless operations. By using the conceptual design methodology (sometimes referred to as bio-mechatronics) a variety of OTS configurations with this capacity was generated. The systematic approach of for targeting the users’ (i.e., the plant management and process operators) needs resulted in better understanding and efficiency in training of hands-on skills in operating the plant. The training included general standard operating procedures for running the plant under normal operation conditions with different starch materials, handling of typical frequent disturbances as well as acting in situations not described in the standard operation procedures and applying trouble-shooting

  • 111.
    Gerlach, Inga
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska fakulteten. Department of Environmental- and Bio-Technology, Hochschule Bremen University of Applied Sciences Bremen, Bremen, Germany.
    Mandenius, Carl-Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska fakulteten.
    Hass, Volker C.
    Faculty of Medical and Life Sciences, Hochschule Furtwangen University of Applied Sciences Furtwangen, Germany.
    Operator training simulation for integrating cultivation and homogenisation in protein production2015Inngår i: Biotechnology Reports, ISSN 2215-017X, Vol. 6, s. 91-99Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Operating training simulators (OTS) are virtual simulation tools used for training of process operators in industry in performing procedures and running processes. Based on structured mathematical models of the unit operations of a bioprocess an OTS can train a process operator by visualising changing conditions during the process, allow testing operator actions, testing controller settings, experience unexpected technical problems and getting practice in using prescribed standard procedures for a plant. This work shows the design of an OTS where two sequential steps of a recombinant protein production process, a fed-batch cultivation and a high-pressure homogenisation, are integrated. The OTS was evaluated on a user test group and showed that the OTS promoted and developed their understanding of the process, their capability to identify parameters influencing process efficiency and the skills of operating it.

  • 112.
    Gerlach, Inga
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska högskolan. University of Applied Sciences, Bremen, Germany.
    Tholin, Sören
    Lantmännen Reppe AB, Lidköping, Sweden.
    Hass, Volker C.
    Hochschule Furtwangen University of Applied Sciences Furtwangen, Villingen- Schwenningen, Germany.
    Mandenius, Carl-Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska högskolan.
    Operator training simulator for an industrial bio-ethanol plant2015Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The development of a software-based operator training simulators (OTS) for an industrial bioethanol plant is described. OTS are used in the process industry for training of process operators since several years but few examples are reported for their use in biochemical and biotechnological industry. This study describes the implementation of an OTS at a large-scale bio-plant producing ethanol. The study includes the implementation of models and graphical user interfaces of the OTS as well as the experience of the operator training with it. The OTS encompasses the whole process, i.e. the sections for hydrolysis, fermentation, separation and distillation. The implementation was carried out on the commercial process control software WinErs. The graphical user interfaces, including all essential distributed control systems of the plant, show high fidelity with the real system. Dynamic process models were able to efficiently train operators in running and controlling the process under standard, start-up, shut-down and critical conditions. The models show a sufficient accuracy and robustness at different simulation speeds. Experiences of applying the OTS in the industrial operator environment of the large-scale plant implies that the OTS can be a useful tool for making operator training more time- and cost-efficient in the biochemical and biotechnological industry.

  • 113.
    Ginesy, Mireille
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Production of L-arginine by genetically modified Escherichia coli2015Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In the recent years, the demand for environmental friendly produced L-arginine has risen with the increasing number of applications for this amino acid in pharmaceuticals, nutraceuticals, cosmetics, animal feed and fertilizers. Members of the Corynebacteriaceae family are usually used for microbial L-arginine production. However, Escherichia coli present the advantage of being able to utilize a wider range of substrates, including pentose sugars found in lignocellulosic feedstocks. The present thesis illustrates the first steps in the development of a sustainable process to produce L-arginine using E. coli. It starts with the constructions of a L-arginine overproducing strain, followed by optimization of the nitrogen supply for the fermentations.The first part of this thesis aimed at engineering an E. coli train able to produce high level of L-arginine. Mutations on key genes of the L-arginine biosynthesis pathway were step-wisely done. The mutants obtained at each step were tested in bioreactor fermentations to assess the effect of each genetic modification. The final strain was able to produce almost 12 g/l during fermentation, at a productivity of 0.24 g/l/h. In comparison the starting strain, E. coli K12 C600, was not able to excrete any L-arginine. To minimize nitrogen wastes and optimize the L-arginine production the impact of different nitrogen sources and concentration were investigated. It was shown that while ammonium phosphate dibasic was the most potent nitrogen source during cultivation on complex medium, all the sources were equivalent with minimal media; this probably reflected the phosphate deficiency of the complex medium used. In fermentation on minimal medium, a carbon to nitrogen ratio of 5 was demonstrated to be the most suitable, yielding up to 4.5 g/l L-arginine. At this ratio, both glucose and the nitrogen source were completely utilized during fermentation.

  • 114.
    Ginesy, Mireille
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Belotserkovsky, Jaroslav
    Department of Molecular Biosciences Wenner-Gren institute, Stockholm University.
    Enman, Josefine
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Isaksson, Leif
    Department of Molecular Biosciences Wenner-Gren institute, Stockholm University.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Metabolic engineering of Escherichia coli for enhanced arginine biosynthesis2015Inngår i: Microbial Cell Factories, ISSN 1475-2859, E-ISSN 1475-2859, Vol. 14, nr 1, artikkel-id 29Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BackgroundArginine is a high-value product, especially for the pharmaceutical industry. Growing demand for environmental-friendly and traceable products have stressed the need for microbial production of this amino acid. Therefore, the aim of this study was to improve arginine production in Escherichia coli by metabolic engineering and to establish a fermentation process in 1-L bioreactor scale to evaluate the different mutants. ResultsFirstly, argR (encoding an arginine responsive repressor protein), speC, speF (encoding ornithine decarboxylases) and adiA (encoding an arginine decarboxylase) were knocked out and the feedback-resistant argA214 or argA215 were introduced into the strain. Three glutamate independent mutants were assessed in bioreactors. Unlike the parent strain, which did not excrete any arginine during glucose fermentation, the constructs produced between 1.94 and 3.03 g/L arginine. Next, wild type argA was deleted and the gene copy number of argA214 was raised, resulting in a slight increase in arginine production (4.11 g/L) but causing most of the carbon flow to be redirected toward acetate. The V216A mutation in argP (transcriptional regulator of argO, which encodes for an arginine exporter) was identified as a potential candidate for improved arginine production. The combination of multicopy of argP216 or argO and argA214 led to nearly 2-fold and 3-fold increase in arginine production, respectively, and a reduction of acetate formation. ConclusionsIn this study, E. coli was successfully engineered for enhanced arginine production. The ∆adiA, ∆speC, ∆speF, ∆argR, ∆argA mutant with high gene copy number of argA214 and argO produced 11.64 g/L of arginine in batch fermentation, thereby demonstrating the potential of E. coli as an industrial producer of arginine.

  • 115.
    Ginesy, Mireille
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Enman, Josefine
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rusanova-Naydenova, Daniela
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Simultaneous Quantification of L-Arginine and Monosaccharides during Fermentation: An Advanced Chromatography Approach2019Inngår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 24, nr 4, artikkel-id 802Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Increasing demand for L-arginine by the food and pharmaceutical industries has sparked the search for sustainable ways of producing it. Microbial fermentation offers a suitable alternative; however, monitoring of arginine production and carbon source uptake during fermentation, requires simple and reliable quantitative methods compatible with the fermentation medium. Two methods for the simultaneous quantification of arginine and glucose or xylose are described here: high-performance anion-exchange chromatography coupled to integrated pulsed amperometric detection (HPAEC-IPAD) and reversed-phase ultra-high-performance liquid chromatography combined with charged aerosol detection (RP-UHPLC-CAD). Both were thoroughly validated in a lysogeny broth, a minimal medium, and a complex medium containing corn steep liquor. HPAEC-IPAD displayed an excellent specificity, accuracy, and precision for arginine, glucose, and xylose in minimal medium and lysogeny broth, whereas specificity and accuracy for arginine were somewhat lower in medium containing corn steep liquor. RP-UHPLC-CAD exhibited high accuracy and precision, and enabled successful monitoring of arginine and glucose or xylose in all media. The present study describes the first successful application of the above chromatographic methods for the determination and monitoring of L-arginine amounts during its fermentative production by a genetically modified Escherichia coli strain cultivated in various growth media.

  • 116.
    Ginesy, Mireille
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rusanova-Naydenova, Daniela
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Tuning of the Carbon-to-Nitrogen Ratio for the Production of L-Arginine by Escherichia coli2017Inngår i: Fermentation, ISSN 2311-5637, Vol. 3, nr 4, artikkel-id 60Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    L-arginine, an amino acid with a growing range of applications within the pharmaceutical, cosmetic, food, and agricultural industries, can be produced by microbial fermentation. Although it is the most nitrogen-rich amino acid, reports on the nitrogen supply for its fermentation are scarce. In this study, the nitrogen supply for the production of l-arginine by a genetically modified Escherichia coli strain was optimised in bioreactors. Different nitrogen sources were screened and ammonia solution, ammonium sulphate, ammonium phosphate dibasic, and ammonium chloride were the most favourable nitrogen sources for l-arginine synthesis. The key role of the C/N ratio for l-arginine production was demonstrated for the first time. The optimal C/N molar ratio to maximise l-arginine production while minimising nitrogen waste was found to be 6, yielding approximately 2.25 g/L of l-arginine from 15 g/L glucose with a productivity of around 0.11 g/L/h. Glucose and ammonium ion were simultaneously utilized, showing that this ratio provided a well-balanced equilibrium between carbon and nitrogen metabolisms.

  • 117.
    Glassner, David A.
    et al.
    National Renewable Energy Laboratory, Golden, Colorado.
    Elankovan, Ponnam
    Michigan Biotechnology Institute, Lansing.
    Beacom, Daniel R.
    Michigan Biotechnology Institute, Lansing.
    Berglund, Kris
    Purification process for succinic acid produced by fermentation1995Inngår i: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, Vol. 51, nr 1, s. 73-82Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Succinic acid is a versatile four-carbon dicarboxylic acid. It can be used commerically as an intermediate chemical for the manufacture of 1,4-butanediol, maleic anhydride, and many other chemicals. Succinic acid can be produced by the fermentation of carbohydrates. A complete process for the production and purification of succinic acid from carbohydrates has been developed. The process includes fermentation, desalting electrodialysis, water-splitting electrodialysis, and crystallization to produce a pure crystalline succinic acid. This article will present experimental work performed in the development of this process.

  • 118.
    Gowtham, Yogender Kumar
    et al.
    Clemson University.
    Miller, Kristen P.
    Clemson University.
    Hodge, David
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Henson, J. Michael
    Clemson University.
    Harcum, Sarah W.
    Clemson University.
    Novel two-stage fermentation process for bioethanol production using Saccharomyces pastorianus2014Inngår i: Biotechnology progress (Print), ISSN 8756-7938, E-ISSN 1520-6033, Vol. 30, nr 2, s. 300-310Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bioethanol produced from lignocellulosic materials has the potential to be economically feasible, if both glucose and xylose released from cellulose and hemicellulose can be efficiently converted to ethanol. Saccharomyces spp. can efficiently convert glucose to ethanol; however, xylose conversion to ethanol is a major hurdle due to lack of xylose-metabolizing pathways. In this study, a novel two-stage fermentation process was investigated to improve bioethanol productivity. In this process, xylose is converted into biomass via non-Saccharomyces microorganism and coupled to a glucose-utilizing Saccharomyces fermentation. Escherichia coli was determined to efficiently convert xylose to biomass, which was then killed to produce E. coli extract. Since earlier studies with Saccharomyces pastorianus demonstrated that xylose isomerase increased ethanol productivities on pure sugars, the addition of both E. coli extract and xylose isomerase to S. pastorianus fermentations on pure sugars and corn stover hydrolysates were investigated. It was determined that the xylose isomerase addition increased ethanol productivities on pure sugars but was not as effective alone on the corn stover hydrolysates. It was observed that the E. coli extract addition increased ethanol productivities on both corn stover hydrolysates and pure sugars. The ethanol productivities observed on the corn stover hydrolysates with the E. coli extract addition was the same as observed on pure sugars with both E. coli extract and xylose isomerase additions. These results indicate that the two-stage fermentation process has the capability to be a competitive alternative to recombinant Saccharomyces cerevisiae-based fermentations.

  • 119.
    Graiver, D.
    et al.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Dacomba, R.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Khawali, M.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Jaros, Adam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Narayan, R.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Steel-corrosion inhibitors derived from soybean oil2012Inngår i: Journal of the American Oil Chemists Society, ISSN 0003-021X, E-ISSN 1558-9331, Vol. 89, nr 10, s. 1895-1903Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Soybean oil derivatives containing a Schiff-base (SOS-B) were prepared and evaluated as microbial corrosion inhibitors against sulfate-reducing bacteria using the gram-positive Desulfosporosinus orientis bacteria as a representative bacterium. These SOS-B compounds were also found to be excellent inhibitors against acidic corrosion of carbon steel. These soybean oil derivatives were prepared by ozonation of soybean oil to yield aldehyde functional intermediates which were then reacted with benzylamine to produce a mixture of imine functional triglycerides and linear compounds. The structure of these soy-based derivatives was confirmed by FTIR and NMR. It was found that the addition of these SOS-B compounds to D. orientis culture provided a complete inhibition of this bacterium. Furthermore, almost no corrosion of carbon steel panels was observed when the panels were aged in 2N HCl solution containing 10 ppm of these SOS-B compounds

  • 120.
    Gustafsson, Anki
    et al.
    Recopharma AB, Huddinge.
    Sjöblom, Magnus
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Strindelius, Lena
    Recopharma AB, Huddinge.
    Johansson, Thomas
    Recopharma AB, Huddinge.
    Fleckenstein, Tilly
    Recopharma AB, Huddinge.
    Chatzissavidou, Nathalie
    Recopharma AB, Huddinge.
    Lindberg, Linda
    Absorber AB, Stockholm.
    Ångström, Jonas
    Göteborgs universitet.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Holgersson, Jan
    Karolinska Institutet.
    Pichia pastoris-produced mucin-type fusion proteins with multivalent O-glycan substitution as targeting molecules for mannose-specific receptors of the immune system2011Inngår i: Glycobiology, ISSN 0959-6658, E-ISSN 1460-2423, Vol. 21, nr 8, s. 1071-1086Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mannose-binding proteins like the macrophage mannose receptor (MR), the dendritic cell-specific intercellular adhesion molecule-3 grabbing non-integrin (DC-SIGN) and mannose-binding lectin (MBL) play crucial roles in both innate and adaptive immune responses. Immunoglobulin fusion proteins of the P-selectin glycoprotein ligand-1 (PSGL-1/mIgG2b) carrying mostly O-glycans and, as a control, the a1-acid glycoprotein (AGP/mIgG2b) carrying mainly N-linked glycans were stably expressed in the yeast Pichia pastoris. P. pastoris-produced PSGL-1/mIgG2b was shown to carry O-glycans that mediated strong binding to mannose-specific lectins in a lectin array and were susceptible to cleavage by a-mannosidases including an a1,2- but not an a1,6-mannosidase. Electrospray ionization - ion trap mass spectrometry (ESI-MS) confirmed the presence of O-glycans containing up to 9 hexoses with the penta- and hexasaccharides being the predominant ones. a1,2- and a1,3-linked, but not a1,6-linked, mannose residues were detected by 1H-nuclear magnetic resonance (1H-NMR) spectroscopy confirming the results of the mannosidase cleavage. The apparent equilibrium dissociation constants for binding of PNGase F-treated mannosylated PSGL-1/mIgG2b to MR, DC-SIGN and MBL were shown by surface plasmon resonance to be 126, 56 and 16 nM, respectively. In conclusion, PSGL-1/mIgG2b expressed in P. pastoris carried O-glycans mainly comprised of a-linked mannoses and with up to nine residues. It bound mannose-specific receptors with high apparent affinity and may become a potent targeting molecule for these receptors in vivo.

  • 121.
    Gustavsson, Martin
    KTH, Skolan för bioteknologi (BIO), Bioprocessteknik (stängd 20130101).
    Influence of recombinant passenger properties and process conditions on surface expression using the AIDA-I autotransporter2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Surface expression has attracted much recent interest, and it has been suggested for a variety of applications. Two such applications are whole-cell biocatalysis and the creation of live vaccines. For successful implementation of these applications there is a need for flexible surface expression systems that can yield a high level of expression with a variety of recombinant fusion proteins. The aim of this work was thus to create a surface expression system that would fulfil these requirements.

     

    A novel surface expression system based on the AIDA-I autotransporter was created with the key qualities being are good, protein-independent detection of the expression through the presence of two epitope tags flanking the recombinant protein, and full modularity of the different components of the expression cassette. To evaluate the flexibility of this construct, 8 different model proteins with potential use as live-vaccines or biocatalysts were expressed and their surface expression levels were analysed.

     

    Positive signals were detected for all of the studied proteins using antibody labelling followed by flow cytometric analysis, showing the functionality of the expression system. The ratio of the signal from the two epitope tags indicated that several of the studied proteins were present mainly in proteolytically degraded forms, which was confirmed by Western blot analysis of the outer membrane protein fraction. This proteolysis was suggested to be due to protein-dependent stalling of translocation intermediates in the periplasm, with indications that larger size and higher cysteine content had a negative impact on expression levels. Process design with reduced cultivation pH and temperature was used to increase total surface expression yield of one of the model proteins by 400 %, with a simultaneous reduction of proteolysis by a third. While not sufficient to completely remove proteolysis, this shows that process design can be used to greatly increase surface expression. Thus, it is recommended that future work combine this with engineering of the bacterial strain or the expression system in order to overcome the observed proteolysis and maximise the yield of surface expressed protein.

  • 122.
    Gustavsson, Martin
    KTH, Skolan för bioteknologi (BIO), Bioprocessteknik.
    Surface expression using the AIDA autotransporter:  Towards live vaccines and whole-cell biocatalysis2011Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The area of surface expression has gathered a lot of interest from research groups all over the world and much work is performed in the area. Autotransporters have been used for surface expression in Gram-negative bacteria. One of the more commonly used autotransporters is the Adhesin Involved in Diffuse Adherence (AIDA) of pathogenic Escherichia coli. The surface expression of enzymes and vaccine epitopes offer several advantages. Surface expressed enzymes gain similar properties to immobilised enzymes, mainly simplified handling and separation using centrifugation. Surface expressed vaccine epitopes can have longer half-lives inside the animal that is to be immunized and surface groups on the host cell can act as adjuvants, increasing the immune response and leading to a better immunisation.

      

    However, while much basic research is directed towards mechanisms of surface expression using autotransporters there are few reports regarding production of surface expressed protein. Thus the aim of this work was the optimisation of the yield and productivity of surface expressed protein. Protein Z, an IgG-binding domain of Staphylococcal protein A, was used as a model protein for the investigation of which cultivation parameters influenced surface expression. The choice of cultivation medium gave the largest impact on expression, which was attributed to effects based on the induction of the native promoter of AIDA. The AIDA system was then used for the expression of two Salmonella surface proteins, SefA and H:gm, with potential for use as vaccine epitopes. SefA was verified located on the cell surface, and H:gm was found in the outer membrane of the host cell, though only in proteolytically truncated forms lacking the His6-tag used for detection. This proteolysis persisted in E. coli strains deficient for the outer membrane protease OmpT and was concluded to be dependent on other proteases. The removal of proteolysis and further optimisation of the yield of surface-expressed protein are important goals of further work.

  • 123.
    Gustavsson, Martin
    et al.
    KTH, Skolan för bioteknologi (BIO), Bioprocessteknik.
    Bäcklund, Emma
    KTH, Skolan för bioteknologi (BIO), Bioprocessteknik.
    Larsson, Gen
    KTH, Skolan för bioteknologi (BIO), Bioprocessteknik.
    Optimisation of surface expression using the AIDA autotransporter2011Inngår i: Microbial Cell Factories, ISSN 1475-2859, E-ISSN 1475-2859, Vol. 10Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Bacterial surface display is of interest in many applications, including live vaccine development, screening of protein libraries and the development of whole cell biocatalysts. The goal of this work was to understand which parameters result in production of large quantities of cells that at the same time express desired levels of the chosen protein on the cell surface. For this purpose, staphylococcal protein Z was expressed using the AIDA autotransporter in Escherichia coli.

    Results: The use of an OmpT-negative E. coli mutant resulted in successful expression of the protein on the surface, while a clear degradation pattern was found in the wild type. The expression in the mutant resulted also in a more narrow distribution of the surface anchored protein within the population. Medium optimisation showed that minimal medium with glucose gave more than four times as high expression as LB-medium. Glucose limited fed-batch was used to increase the cell productivity and the highest protein levels were found at the highest feed rates. A maintained high surface expression up to cell dry weights of 18 g l(-1) could also be achieved by repeated glucose additions in batch cultivation where production was eventually reduced by low oxygen levels. In spite of this, the distribution in the bacterial population of the surface protein was narrower using the batch technique.

    Conclusions: A number of parameters in recombinant protein production were seen to influence the surface expression of the model protein with respect both to the productivity and to the display on the individual cell. The choice of medium and the cell design to remove proteolytic cleavage were however the most important. Both fed-batch and batch processing can be successfully used, but prolonged batch processing is probably only possible if the chosen strain has a low acetic acid production.

  • 124.
    Gustavsson, Martin
    et al.
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Hörnström, David
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Lundh, Susanna
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Belotserkovsky, Jaroslav
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Larsson, Gen
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Biocatalysis on the surface of Escherichia coli: melanin pigmentation of the cell exterior2016Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, artikkel-id 36117Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Today, it is considered state-of-the-art to engineer living organisms for various biotechnology applications. Even though this has led to numerous scientific breakthroughs, the enclosed interior of bacterial cells still restricts interactions with enzymes, pathways and products due to the mass-transfer barrier formed by the cell envelope. To promote accessibility, we propose engineering of biocatalytic reactions and subsequent product deposition directly on the bacterial surface. As a proof-of-concept, we used the AIDA autotransporter vehicle for Escherichia coli surface expression of tyrosinase and fully oxidized externally added tyrosine to the biopolymer melanin. This resulted in a color change and creation of a black cell exterior. The capture of ninety percent of a pharmaceutical wastewater pollutant followed by regeneration of the cell bound melanin matrix through a simple pH change, shows the superior function and facilitated processing provided by the surface methodology. The broad adsorption spectrum of melanin could also allow removal of other micropollutants.

  • 125.
    Gustavsson, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska fakulteten.
    Development of soft sensors for monitoring and control of bioprocesses2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In the manufacture of bio-therapeutics the importance of a well-known process is key for a high product titer and low batch to batch variations. Soft sensors are based on the concept that online sensor signals can be used as inputs to mathematical models to derive new valuable process information. This information could then be used for better monitoring and control of the bioprocess.

    The aim of the present thesis has been to develop soft sensor solutions for upstream bioprocessing and demonstrate their usefulness in improving robustness and increase the batch-to-batch reproducibility in bioprocesses. The thesis reviews the potential and possibilities with soft sensors for use in production of bio-therapeutics to realize FDA´s process analytical technology (PAT) initiative. Modelling and hardware sensor alternatives which could be used in a soft sensor setup are described and critically analyzed. Different soft sensor approaches to control glucose feeding in fed-batch cultures of Escherichia coli are described. Measurements of metabolic fluxes and specific carbon dioxide production was used as control parameters to increase product yield and decrease the variability of produced recombinant proteins. Metabolic heat signals were used in uninduced cultures to estimate and control the specific growth rate at a desired level and thereby also estimate the biomass concentration online. The introduction of sequential filtering of the signal enabled this method to be used in a down-scaled system. The risk and high impact of contaminations in cell cultures are also described. An in situ microscope (ISM) was used as an online tool to estimate cell concentration and also to determine cell diameter size which enabled the detection of contaminant cells at an early stage.

    The work presented in this thesis supports the idea that soft sensors can be a useful tool in the strive towards robust and reliable bioprocesses, to ensure high product quality and increased economic profit.

  • 126.
    Gustavsson, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi.
    On-line control of glucose feeding in an Escherichia coli fed-batch cultivation expressing a recombinant protein.2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Soft sensors have been suggested as potent tools for on-line estimations of critical bioprocess variables to be able to control the biological process in an as high extent as possible. The formation of inhibitory by-products in the form of organic acids, caused by an overflow of glucose, is a problem in most bioprocesses expressing recombinant proteins. 

     

    In this project a new method of controlling the glucose feeding in an Escherichia coli fed-batch cultivation expressing the green fluorescent protein (GFP) was investigated. The new controller system implemented in the software controlled the feed rate based on on-line HPLC measurements of the concentration of organic acids.   

     

    The results showed that the controller managed to down-regulate the inhibitory organic acids to a low level as it tried to keep the glucose uptake rate at an optimum for maximum cell growth. The results suggested that the controller could be a powerful tool to create a more secure reproducibility and to generate high product yields in recombinant protein productions.   

  • 127.
    Hagman, Linda
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    How do biogas solutions influence the sustainability of bio-based industrial systems?2018Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Biomass is a valuable and limited resource that should be used efficiently. The potential of replacing fossil-based products with bio-based ones produced in biobased industrial systems is huge. One important aim of increasing the share of biobased products is to improve the sustainability of systems for production and consumption. Therefore, it is important to evaluate what solutions are available to improve the sustainability performance of bio-based industrial systems, and if they also bring negative impacts. The thesis focuses on assessing the role of biogas solutions in developing sustainable bio-based systems. Such assessments are often quite narrow in their scope and focus on quantitative environmental or economic aspects. This thesis aims at also including feasibility related aspects involving the contextual conditions that are assessed more qualitatively. Biogas solutions are identified as a versatile approach to treat organic materials which are generated in large volumes in bio-based industrial systems. The results show that biogas solutions in bio-based industrial systems (i) improve circular flows of energy and nutrients, (ii) are especially viable alternatives when the quality of the by-product streams become poorer, and (iii) may improve the profitability of the bio-based industrial system. To perform better assessments of these systems, it seems valuable to broaden the set of indicators assessed and include feasibility-related indicators, preferably through the involvement of relevant stakeholders as they contribute with different perspectives and can identify aspects that influence the sustainability in different areas. Future studies could benefit from applying those broader assessments on more cases to build on a more generalisable knowledge base.

  • 128.
    Hagman, Linda
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    Eklund, Mats
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    Svensson, Niclas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    Assessment of By-product Valorisation in a Swedish Wheat-Based Biorefinery2019Inngår i: Waste and Biomass Valorization, ISSN 1877-2641, E-ISSN 1877-265XArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biorefineries are examples of industries striving towards a circular and bio-based economy through valorising natural raw materials to a spectrum of products. This is a resource-efficient process which also decreases overall environmental impact, as the products from a biorefinery can replace fossil-based products such as plastics or fuels. To become even more resource efficient, an optimisation of the by-product use can increase the performance. This study will evaluate different scenarios for the valorisation of stillage coming from a wheat-based biorefinery. The alternatives range from the direct use of the stillage for fodder, fertiliser or incineration to three different biogas production-based scenarios. The biogas scenarios are divided into the production of fuel at a local or distant plant and the alternative of creating heat and power at the local plant. The results show how locally produced biogas for vehicle fuel and fodder usage are the better alternatives regarding greenhouse gas emissions, the finances of the biorefinery, energy balance and nutrient recycling. The results also indicate that biorefineries with several high-value products may receive lower quality by-product flows, and to these, the biogas solutions become more relevant for valorising stillage while improving value and performance for the biorefinery.

  • 129.
    Hartel, R.W.
    et al.
    Michigan State University.
    Berglund, Kris
    Precipitation kinetics of the titanium isopropoxide hydrolysis reaction1986Inngår i: Better ceramics through chemistry II: symposium held April 15-19, 1986, Palo Alto, California, U.S.A. / [ed] C. Jeffrey Brinker, Materials Research Society, 1986, s. 633-640Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The precipitation product of the titanium isopropoxide (TiPT) hydrolysis reaction was followed using photon correlation spectroscopy. This technique followed the mean size of the precipitate as the reaction progressed as well as giving an indication of the number of particles being produced. From this analysis, the induction time for the onset of nucleation, nucleation rate (or the rate of particle production) and mean growth rate were correlated with reactant concentrations. In the concentration ranges studied, the induction time was an inverse function of reactant concentrations. Both nucleation rate and average growth rate increase as reactant concentration increased, with the TiPT concentration being more important. This reaction was also followed using absorbance spectrophotometry in the 500 to 320 nm range. After mixing of the reactants, an absorbance peak was seen between 330 and 335 nm, depending on the conditions. This peak increased slowly during the induction period and then increased rapidly after the onset of nucleation due to increasing turbidity

  • 130. Hartel, R.W.
    et al.
    Berglund, Kris
    Gwynn, S.M.
    Schierholz, P.M.
    Murphy, V.G:
    Crystallization kinetics for the sucrose-water system1980Inngår i: Design, control and analysis of crystallization processes / [ed] Alan D. Randolph, American Institute of Chemical Engineers, 1980, s. 65-72Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Crystallization kinetics for the sucrose-water system were studied in a continuous MSMPR cooling crystallizer. Growth and nucleation rates were derived from the measured size distributions using the population balance equation. In the region of higher supersaturation, where secondary nucleation occurs, it appeared that growth was a linear function of supersaturation; whereas, nucleation was approximately 1. 5 order in supersaturation. Growth rates were lower for crystals smaller than about 60 mu m, although these too increased with supersaturation. The latter trends were observed in both the higher (nucleating) and lower (non-nucleating) supersaturation regions. Preliminary batch studies indicated that the rate of secondary nucleation was also a function of both the method of contact and the impact energy.

  • 131.
    Helmerius, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Integration of a hemicelluloses extraction step into a forest biorefinery for production of green chemicals2010Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Sustainable use of forest and agricultural resources will play an important role for solving urgent global challenges such as the enhanced green house effect and increasing demand for fossil fuels. The development of processes where lignocellulosic biomass can be refined to several different end-products in the same plant, i.e. a biorefinary, will be important in the development towards a more sustainable society where fossil fuels are replaced. To be able to compete with fossil resources, an efficient production of biomass based products is required in order to maximize overall process economics and to minimize negative environmental impact. One solution to increase profitability for forest biomass based plants can be production of value added derivatives produced through fermentation of sugars from hemicelluloses, extracted from lignocellulosic material. The first part of this thesis investigate the impact of hemicellulose pre-extraction on birch Kraft pulp properties. White liquor and water extractions of hemicelluloses from birch wood chips were performed under conditions compatible with Kraft pulping. The chips from select extractions were subject to subsequent Kraft pulping and the refined pulps were made into hand sheets. Several metrics for hand sheet strength properties were compared with a reference pulp made without an extraction step. This work also includes a demonstration of enzymatic hydrolysis and biological conversion of extracted xylan to succinic acid, a metabolite with the potential of a platform chemical. The study demonstrated that white liquor can be utilized to extract xylan from birch wood chips prior to Kraft cooking without decreasing the pulp yield and paper strength properties, while simultaneously impregnating cooking alkali into the wood chips. Alkaline conditions tested above pH 10 significantly degraded xylan and very low concentrations of xylose were obtained using any of the alkaline extractions. Water extractions resulted in the highest final concentration of xylose, 29.1 g/L; yielding fermentable liquor, but were found to negatively impact some pulp properties including decreases in compression strength, bursting strength, tensile strength and tensile stiffness while exhibiting minimal impact on elongation and slight improvement in tearing strength index. Since hot water extractions gave fermentable liquors, the next study was to integrate the production of green chemicals via hot water hemicellulose extraction of birch wood into a small-scale combined heat and power plant, in this case an externally fired gas turbine. The results show that the extracted wood chips would serve very well as a fuel for combustion and gasification processes due to the relatively high heating value. Most important, the extracted wood chips had low ash content and significantly lower concentrations of alkali metals. In addition a fermentable stream with a xylose concentration of 65 g/L was produced.The second part of this thesis was to optimise the production of the dicarboxylic acid, succinic acid, which can be produced via bioconversion as a renewable building block molecule for production of biodegradable solvents and polyesters. In this study the E. coli strain AFP184, which can ferment both five and six carbon sugars with a limited production of other organic acids was used. Earlier work using a high initial sugar concentration resulted in volumetric productivities of almost 3 g/L h, which is above estimated values for economically feasible production, and final succinic acid concentration was around 40 g/L. To further increase succinic acid concentrations, fermentations using NH4OH, NaOH, KOH, K2CO3, and Na2CO3 as neutralising agents were performed and compared. It was shown that substantial improvements could be made by using alkali bases to neutralise the fermentations. The highest concentrations and productivities were achieved when Na2CO3 was used, 77 g/L and 3 g/L h, respectively. A gradual decrease in succinate productivity was observed during the fermentations, which was shown to be due to succinate accumulation in the broth and not as a result of the addition of neutralising agent or the subsequent increase in osmolarity.

  • 132. Helmerius, Jonas
    et al.
    Walter, Jonas Vinblad von
    Smurfit Kappa Kraftliner AB.
    Rova, Ulrika
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hodge, David
    Production of value added chemicals from xylan extraction in a Kraft pulp mill and the effect on pulp quality2008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In the Kraft process hemicelluloses are lost in the cooking procedure to the black liquor stream, which is subsequently burnt in the recovery boiler to recover cooking chemicals and to produce steam and energy. Hemicelluloses have a low heating value compared to lignin and therefore recovery of hemicelluloses at an earlier stage of the Kraft process followed by biochemical conversionintohighvalue-conversion intohighvalue-into high value-added products might offer a muchbettereconomicopportunity.much better economic opportunityIn collaboration with the research and development department of Smurfit Kappa Kraftliner AB, Piteå, Sweden, alkali and water extractions of birch wood were performed under conditions compatible with the Kraft process, at different times, temperatures and alkali charges. The extraction conditions were set in a range suitable with the current pulp process at Smurfit Kappa Kraftliner. TherequirementsforprocessThe requirements for process configurations, based on either hot water or alkali extraction were also explored. ThexylanyieldsfromdifferentextractiontrialswereThe xylan yields from different extraction trials were measured and the chips from those extraction trials were cooked, refined and turned into sheets of paper. The effects on paper quality were compared with a reference pulp made from the same wooden chips. Recovered xylans from water extracted birch wood chips were subjected to secondary hydrolysis, enzymatic or sulphuricacid.sulphuric acidDetoxification of the hydrolysate with active carbon and regulation of pH were performed before fermentation. FermentationofthexyloseFermentation of the xylose hydrolysate to succinic acid was demonstrated by the use of thethe succinic acid producer Escherichia coli AFP184.

  • 133. Helmerius, Jonas
    et al.
    Walter, Jonas Vinblad von
    Smurfit Kappa Kraftliner AB.
    Rova, Ulrika
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hodge, David
    Production of value added chemicals from xylan extraction in a Kraft pulp mill and the effect on pulp quality2008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In the Kraft process hemicelluloses are lost in the cooking procedure to the black liquor stream, which is subsequently burnt in the recovery boiler to recover cooking chemicals and to produce steam and energy. Hemicelluloses have a low heating value compared to lignin and therefore recovery of hemicelluloses at an earlier stage of the Kraft process followed by biochemical conversion into high value-added products might offer a much better economic opportunity. In collaboration with the research and development department of Smurfit Kappa Kraftliner AB, Piteå, Sweden, alkali and water extractions of birch wood were performed under conditions compatible with the Kraft process, at different times, temperatures and alkali charges. The extraction conditions were set in a range suitable with the current pulp process at Smurfit Kappa Kraftliner. The requirements for process configurations, based on either hot water or alkali extraction were also explored. The xylan yields from different extraction trials were measured and the chips from those extraction trials were cooked, refined and turned into sheets of paper. The effects on paper quality were compared with a reference pulp made from the same wooden chips. Recovered xylans from water extracted birch wood chips were subjected to secondary hydrolysis, enzymatic or sulphuric acid. Detoxification of the hydrolysate with active carbon and regulation of pH were performed before fermentation. Fermentation of the xylose hydrolysate to succinic acid was demonstrated by the use of the succinic acid producer Escherichia coli AFP184.

  • 134.
    Helmerius, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Walter, Jonas Vinblad von
    Luleå tekniska universitet.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Berglund, Kris
    Hodge, David B.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Impact of hemicellulose pre-extraction for bioconversion on birch Kraft pulp properties2010Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 101, nr 15, s. 5996-6005Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The combination of hemicellulose extraction with chemical pulping processes is one approach to generate a sugar feedstock amenable to biochemical transformation to fuels and chemicals. Extractions of hemicellulose from silver birch (Betula pendula) wood chips using either water or Kraft white liquor (NaOH, Na2S, and Na2CO3) were performed under conditions compatible with Kraft pulping, using times ranging between 20 and 90 min, temperatures of 130-160 °C, and effective alkali (EA) charges of 0-7%. The chips from select extractions were subjected to subsequent Kraft pulping and the refined pulps were made into handsheets. Several metrics for handsheet strength properties were compared with a reference pulp made without an extraction step. This study demonstrated that white liquor can be utilized to extract xylan from birch wood chips prior to Kraft cooking without decreasing the pulp yield and paper strength properties, while simultaneously impregnating cooking alkali into the wood chips. However, for the alkaline conditions tested extractions above pH 10 resulted in low concentrations of xylan. Water extractions resulted in the highest final concentrations of xylan; yielding a liquor without the presence of toxic or inhibitory inorganics and minimal soluble aromatics that we demonstrate can be successfully enzymatically hydrolyzed to monomeric xylose and fermented to succinic acid. However, water extractions were found to negatively impact some pulp properties including decreases in compression strength, bursting strength, tensile strength, and tensile stiffness while exhibiting minimal impact on elongation and slight improvement in tearing strength index.

  • 135. Hodge, David
    et al.
    Andersson, Christian
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Rova, Ulrika
    Detoxification requirements for bioconversion of softwood dilute acid hydrolyzates to succinic acid2009Inngår i: Enzyme and microbial technology, ISSN 0141-0229, E-ISSN 1879-0909, Vol. 44, nr 5, s. 309-316Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work an Escherichia coli metabolically engineered to ferment lignocellulosic biomass sugars to succinic acid was tested for growth and fermentation of detoxified softwood dilute sulfuric acid hydrolyzates, and the minimum detoxification requirements were investigated with activated carbon and/or overliming treatments. Detoxified hydrolyzates supported fast growth and complete fermentation of all hydrolyzate sugars to succinate at yields comparable to pure sugar, while untreated hydrolyzates were unable to support either growth or fermentation. Activated carbon treatment was able to remove significantly more HMF and phenolics than overliming. However, in some cases, overliming treatment was capable of generating a fermentable hydrolyzate where activated carbon treatment was not. The implications of this are that in addition to the known organic inhibitors, the changes in the inorganic content and/or composition due to overliming are significant to the hydrolyzate toxicity. It was also found that any HMF remaining after detoxification was completely metabolized during aerobic cell growth on the hydrolyzates that were capable of supporting growth.

  • 136. Hodge, David
    et al.
    Andersson, Christian
    Helmerius, Jonas
    Walter, J. Vinblad von
    Rova, Ulrika
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Succinic acid production from forest based raw materials2008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Lignocellulosic biomass and particularly hemicellulose from the forest products industry represents a large reservoir of sugars with the potential to be converted to higher value products through bioprocessing. This presentation will cover several projects regarding the fractionation and conversion of lignocellulose to succinic acid, a potentially important platform molecule in the synthesis of a number of commodity and specialty chemicals. The first of these investigates the feasibility of integrating a hardwood hemicellulose sugar extraction step into a Kraft pulping process with the intention of utilizing the hemicellulose as a fermentation feedstock. The requirements on processing configurations for hemicellulose extraction and recovery are compared, and a number of experimental parameters affecting the extraction (alkali, temperature, time) are investigated. Pulp quality is an important property and hemicellulose extraction can result in negatively affect the strength of the paper, which is also investigated. The second portion of the work deals with the fermentation requirements for microbial conversion of dilute acid hydrolyzed softwood to succinic acid. In particular, activated carbon and overliming detoxifications were tested for the ability to remove fermentation inhibitors and improve the fermentability of the hydrolyzates.

  • 137.
    Hodge, David
    et al.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Helmerius, Jonas
    Walter, Jonas Vinblad von
    Sun Pine Biodiesel AB, Piteå.
    Lindström, Curt
    Smurfit Kappa Kraftliner AB, Piteå.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Impact of hemicellulose pre-extraction for bioconversion on birch kraft pulp properties2009Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The carbohydrate portion of lignocellulosic feedstocks are ideally suited to conversion via biochemical transformations because of their crucial role in cellular metabolism. The combination of hemicelluloses extraction with pulping processes could be one way to generate a sugar feedstock amenable to biochemical transformation to fuels and chemical intermediates. White liquor, green liquor, and water HC extractions of birch wood were performed under conditions compatible with the Kraft process, at different times, temperatures and alkali charges. The effective alkali charge was in extractions between 0%-7% and temperature between 130°C-160°C for 20-90 minutes. The xylan yields from different HC extractions were measured and the chips from select HC extractions were cooked, and the refined pulps were made into hand sheets. Several metrics for hand sheet quality were compared with a reference pulp made from the same wood chips. It is possible using white liquor to extract xylan from birch wood chips prior Kraft cooking without decreasing the pulp yield and paper strength properties, and at the same time achieve an impregnation of the wood chips. It is not possible in that extraction to attain extracted and hydrolyzed liquor containing a fermentable concentration of xylose, 2.63 g/L in this study. Increased extracted wood material, increased final acetic acid concentration and decreased final xylan concentration together with increased effective alkali charge at the same extraction temperature and time in white liquor extractions performed support that xylan degradation increases. Using white liquor or green liquor under the conditions investigated degrades xylan resulting in significant losses of xylose that could have been used as substrate in fermentation processes.

  • 138.
    Hodge, David
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Karim, M. Nazmul
    Texas Tech University, Department of Chemical Engineering.
    Schell, Daniel J.
    National Renewable Energy Laboratory, National Bioenergy Center.
    McMillan, James D.
    National Renewable Energy Laboratory, National Bioenergy Center.
    Model-based fed-batch for high-solids enzymatic cellulose hydrolysis2009Inngår i: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, Vol. 152, nr 1, s. 88-107Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    While many kinetic models have been developed for the enzymatic hydrolysis of cellulose, few have been extensively applied for process design, optimization, or control. High-solids operation of the enzymatic hydrolysis of lignocellulose is motivated by both its operation decreasing capital costs and increasing product concentration and hence separation costs. This work utilizes both insights obtained from experimental work and kinetic modeling to develop an optimization strategy for cellulose saccharification at insoluble solids levels greater than 15% (w/w), where mixing in stirred tank reactors (STRs) becomes problematic. A previously developed model for batch enzymatic hydrolysis of cellulose was modified to consider the effects of feeding in the context of fed-batch operation. By solving the set of model differential equations, a feeding profile was developed to maintain the insoluble solids concentration at a constant or manageable level throughout the course of the reaction. Using this approach, a stream of relatively concentrated solids (and cellulase enzymes) can be used to increase the final sugar concentration within the reactor without requiring the high initial levels of insoluble solids that would be required if the operation were performed in batch mode. Experimental application in bench-scale STRs using a feed stream of dilute acid-pretreated corn stover solids and cellulase enzymes resulted in similar cellulose conversion profiles to those achieved in batch shake-flask reactors where temperature control issues are mitigated. Final cellulose conversions reached approximately 80% of theoretical for fed-batch STRs fed to reach a cumulative solids level of 25% (w/w) initial insoluble solids

  • 139. Hodge, David
    et al.
    Karim, M.N.
    Texas Tech University, Lubbock.
    Schell, D.J.
    National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO.
    McMillan, J.D.
    National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO.
    Soluble and insoluble solids contributions to high-solids enzymatic hydrolysis of lignocellulose2008Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 99, nr 18, s. 8940-8948Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The rates and extents of enzymatic cellulose hydrolysis of dilute acid pretreated corn stover (PCS) decline with increasing slurry concentration. However, mass transfer limitations are not apparent until insoluble solids concentrations approach 20% w/w, indicating that inhibition of enzyme hydrolysis at lower solids concentrations is primarily due to soluble components. Consequently, the inhibitory effects of pH-adjusted pretreatment liquor on the enzymatic hydrolysis of PCS were investigated. A response surface methodology (RSM) was applied to empirically model how hydrolysis performance varied as a function of enzyme loading (12-40 mg protein/g cellulose) and insoluble solids concentration (5-13%) in full-slurry hydrolyzates. Factorial design and analysis of variance (ANOVA) were also used to assess the contribution of the major classes of soluble components (acetic acid, phenolics, furans, sugars) to total inhibition. High sugar concentrations (130 g/L total initial background sugars) were shown to be the primary cause of performance inhibition, with acetic acid (15 g/L) only slightly inhibiting enzymatic hydrolysis and phenolic compounds (9 g/L total including vanillin, syringaldehyde, and 4-hydroxycinnamic acid) and furans (8 g/L total of furfural and hydroxymethylfurfural, HMF) with only a minor effect on reaction kinetics. It was also demonstrated that this enzyme inhibition in high-solids PCS slurries can be approximated using a synthetic hydrolyzate composed of pure sugars supplemented with a mixture of acetic acid, furans, and phenolic compounds, which indicates that generally all of the reaction rate-determining soluble compounds for this system can be approximated synthetically.

  • 140.
    Hodge, David
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Stoklosa, Ryan J.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Extraction, recovery, and characterization of hardwood and grass hemicelluloses for integration into biorefining processes2012Inngår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 51, nr 34, s. 11045-11053Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For this work, four hardwoods (silver birch, sugar maple, a hybrid poplar, and a hybrid aspen) and one cultivar of switchgrass were treated with increasing levels of NaOH. The recovered cell wall biopolymers were characterized based on total extraction, precipitation using ethanol or acidification, xylan content, and molar mass of the recovered precipitates. The extractability of cell wall polymers was clearly shown to be a function of the biomass type with more than 50% of the cell walls of switchgrass solubilized by alkali while only up to 20% of the maple was solubilized under comparable conditions. Precipitation with ethanol resulted in high recovery yields of hemicelluloses from the original biomass for silver birch and switchgrass, and most notably, the birch precipitates contained double the hemicellulose content of the precipitates from other feedstock alkali extracts (80% versus 30-50%). The molar masses of the recovered hemicellulosic polysaccharides were characterized using size exclusion chromatography (SEC) and an assay to quantify polysaccharide reducing ends. SEC analysis showed that the biopolymers exhibited a strong tendency to self-associate during elution and that this aggregation could be eliminated through sonication. The reducing end method showed an increase in the number-average degree of polymerization toward an asymptotic maximum with increasing extraction pH, and this value was significantly increased by bleaching the precipitate to remove interference by nonpolysaccharides

  • 141.
    Hu, Shu-Hong
    et al.
    Centre for Drug Design and Development and Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, University of Queensland.
    Gee, Christine L.
    Centre for Drug Design and Development and Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, University of Queensland.
    Latham, Catherine F.
    Centre for Drug Design and Development and Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, University of Queensland.
    Rowlinson, Scott W.
    Centre for Drug Design and Development and Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, University of Queensland.
    Rova, Ulrika
    Jones, Alun
    Centre for Drug Design and Development and Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, University of Queensland.
    Halliday, Judy A.
    Centre for Drug Design and Development and Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, University of Queensland.
    Bryant, Nia J.
    Wellcome Laboratory of Cell Biology, Institute of Biomedical and Life Sciences, Division of Biochemistry and Molecular Biology, The University of Glasgow.
    James, David E.
    Garvan Institute of Medical Research, 384 Victoria Road, Darlinghurst, Sydney.
    Martin, Jennifer F.
    Centre for Drug Design and Development and Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, University of Queensland.
    Recombinant expression of Munc18c in a baculovirus system and interaction with syntaxin42003Inngår i: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 31, nr 2, s. 305-310Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two protein families that are critical for vesicle transport are the Syntaxin and Munc18/Sec1 families of proteins. These two molecules form a high affinity complex and play an essential role in vesicle docking and fusion. Munc18c was expressed as an N-terminally His-tagged fusion protein from recombinant baculovirus in Sf9 insect cells. His-tagged Munc18c was purified to homogeneity using both cobalt-chelating affinity chromatography and gel filtration chromatography. With this simple two-step protocol, 3.5 mg of purified Munc18c was obtained from a 1 L culture. Further, the N-terminal His-tag could be removed by thrombin cleavage while the tagged protein was bound to metal affinity resin. Recombinant Munc18c produced in this way is functional, in that it forms a stable complex with the SNARE interacting partner, syntaxin4. Thus we have developed a method for producing and purifying large amounts of functional Munc18c-both tagged and detagged-from a baculovirus expression system. We have also developed a method to purify the Munc18c:syntaxin4 complex. These methods will be employed for future functional and structural studies.

  • 142.
    Hunt, Cameron J
    et al.
    Department of Chemical Engineering, Monash University, Clayton, 3800, Victoria, Australia..
    Antonopoulou, Io
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Tanksale, Akshat
    Department of Chemical Engineering, Monash University, Clayton, 3800, Victoria, Australia..
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Haritos, Victoria S
    Department of Chemical Engineering, Monash University, Clayton, 3800, Victoria, Australia.
    Insights into substrate binding of ferulic acid esterases by arabinose and methyl hydroxycinnamate esters and molecular docking2017Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, nr 1, artikkel-id 17315Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ferulic acid esterases (FAE, EC 3.1.1.73) cleave the arabinose hydroxycinnamate ester in plant hemicellulose and other related substrates. FAE are commonly categorised as type A-D based on catalytic activities towards model, short alkyl chain esters of hydroxycinnamates. However, this system correlates poorly with sequence and structural features of the enzymes. In this study, we investigated the basis of the type A categorisation of an FAE from Aspergillus niger, AnFaeA, by comparing its activity toward methyl and arabinose hydroxycinnamate esters. kcat/Km ratios revealed that AnFaeA hydrolysed arabinose ferulate 1600-fold, and arabinose caffeate 6.5 times more efficiently than their methyl ester counterparts. Furthermore, small docking studies showed that while all substrates adopted a catalytic orientation with requisite proximity to the catalytic serine, methyl caffeate and methyl p-coumarate preferentially formed alternative non-catalytic conformations that were energetically favoured. Arabinose ferulate was unable to adopt the alternative conformation while arabinose caffeate preferred the catalytic orientation. This study demonstrates that use of short alkyl chain hydroxycinnnamate esters can result in activity misclassification. The findings of this study provide a basis for developing a robust classification system for FAE and form the basis of sequence-function relationships for this class.

  • 143.
    Hussmann, G.A.
    et al.
    Iowa State University.
    Larson, M.A.
    Iowa State University.
    Berglund, Kris
    Characterization of solution structure near the surface of a growing crystal by Raman spectroscopy1984Inngår i: Industrial crystallization 84: proceedings of the 9th Symposium on industrial crystallization, the Hague, the Netherlands, September 25-28, 1984 / [ed] S.J. Jančić; E.J. de Jong, Amsterdam: Elsevier, 1984, s. 21-26Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In situ structure analyses of the supersaturated aqueous NaNO//3 solution near a growing NaNO//3 crystal have been performed using micro Raman spectroscopy. It was observed that the relative concentrations of higher ordered species (contact-ion pairs, and ion aggregates) are diminished near the growing crystal, indicating that these species are dominant in the diffusion process when compared to free aquated ions or solvent-separated ions. There were no detectable differences between the spectra obtained for saturated and supersaturated solutions.

  • 144.
    Häggström, Caroline
    et al.
    Wibax AB.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Brandberg, Tomas
    SEKAB E-Technology, School of Engineering, University of Borås.
    Hodge, David
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Integration of Ethanol Fermentation with Second Generation Biofuels Technologies2014Inngår i: Biorefineries: Integrated Biochemical Processes for Liquid Biofuels, Amsterdam: Elsevier, 2014, s. 161-187Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    This chapter presents an overview of the challenges associated with integrating yeast fermentation into cellulosic biofuel processes, as well as the approaches that might overcome these challenges. The chapter first introduces the design considerations for first-generation ethanol fermentation processes using sugar cane and corn as feedstocks, with an emphasis on process constraints and operation strategies. The chapter then explores methods for improving yield, titer, productivity, and economics. These processing methods illustrate the challenges posed by the fermentation of ethanol from lignocellulose hydrolyzates, especially the differences in process constraints for high-productivity, high-product titer operations. Finally, the chapter discusses an example of aerobic seed cultivation of yeast using a hydrolyzate of dilute acid-hydrolyzed softwood hemicellulose

  • 145. Häggström, Caroline
    et al.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Brandberg, Tomas
    SEKAB E-Technology.
    Hodge, David
    Chemical Engineering & Materials Science, Michigan State University, East Lansing, MI.
    Media requirements for aerobic cultivation of saccharomyces cerevisiae TMB 3400-F30-3 on undetoxified softwood dilute acid hydrolyzate2009Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The purpose of this study was to develop a low-cost industrial nutrient medium for the aerobic cultivation of a hydrolyzate-adapted Saccharomyces cerevisiae TMB3400-FT30-3 for subsequent fermentation of dilute acid hydrolyzed softwood. This xylose-utilizing yeast is a promising ethanologen for converting lignocellulosic biomass sugars to ethanol. The dilute acid pretreated softwood hydrolyzate used in the process is a readily available and economic option for a carbon source for cell growth in the fermentation seed tank and has the added advantage of contributing to cell adaptation before the fermentation. The focus of the work was to determine the minimal level of externally-supplied media supplementation in the form of beet molasses and nitrogen in the form of ammonium sulfate that will still result in near-maximal biomass yields during fed-batch aerobic growth. The experimental work showed that it is possible to supply only 10 % of the sugars in the form of beet molasses (or 6.7 g/L of concentrated molasses ) without any significant reduction of the biomass yield from its near maximum value of 0.45 g biomass / g sugar. It was not until the molasses addition was below 9 % that a statistically significant reduction in yield was observed. Reducing the nitrogen from 0.12 to 0.06 g N / g biomass resulted in a statistically significant decrease of the yield.

  • 146.
    Ingri, Johan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Rodushkin, Ilya
    Malinovskiy, Dmitry
    Hålenius, U.
    Swedish Museum of Natural History.
    Baxter, Douglas
    Andersson, P.S:
    Swedish Museum of Natural History.
    Fractionation of iron isotopes in shallow-marine ferromanganese concretions2007Inngår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 71, nr 15S, s. A428-Artikkel i tidsskrift (Annet vitenskapelig)
  • 147.
    Jansson, Anette
    et al.
    Linnéuniversitetet, Institutionen för byggd miljö och energiteknik (BET).
    Patinvoh, Regina J.
    Lagos State Univ, Nigeria.
    Horvath, Ilona Sarvari
    University of Borås, Sweden.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi. University of Borås, Sweden.
    Dry Anaerobic Digestion of Food and Paper Industry Wastes at Different Solid Contents2019Inngår i: Fermentation - Basel, E-ISSN 2311-5637, Vol. 5, nr 2, s. 1-10, artikkel-id 40Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A large volume of food is being wasted every year, while the pulp and paper industry also generate a large amount of solid wastes on a daily basis, causing environmental challenges around the world. Dry anaerobic digestion (AD) of these solid wastes is a cost-effective method for proper management. However, dry digestion of these waste streams has been restricted due to their complex structure, the presence of possible inhibitors and inappropriate operating conditions. In light of this fact, dry digestion of food waste (FW) and paper wastes (PW) was conducted at different total solid (TS) concentrations of reactor mixtures of 14%, 16%, 18% and 20% TS, corresponding to substrate to inoculum (S/I) ratio of 0.5 and 1; investigating the optimum operating conditions for effective dry digestion of these complex wastes. The highest methane yields of 402 NmlCH(4)/gVS and 229 NmlCH(4)/gVS were obtained from digestion of FW and PW, respectively at 14%TS corresponding to an S/I ratio of 0.5. Increasing the S/I ratio from 0.5 to 1 and thereby having a TS content of 20% in the reactor mixtures was unfavorable to the digestion of both substrates.

  • 148.
    Jansson, Anette
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggd miljö och energiteknik (BET). University of Borås, Sweden.
    Patinvoh, Regina J.
    Lagos State Univ, Nigeria.
    Horvath, Ilona Sarvari
    University of Borås, Sweden.
    Taherzadeh, Mohammad J.
    University of Borås, Sweden.
    Dry Anaerobic Digestion of Food and Paper Industry Wastes at Different Solid Contents2019Inngår i: Fermentation - Basel, E-ISSN 2311-5637, Vol. 5, nr 2, s. 1-10, artikkel-id 40Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A large volume of food is being wasted every year, while the pulp and paper industry also generate a large amount of solid wastes on a daily basis, causing environmental challenges around the world. Dry anaerobic digestion (AD) of these solid wastes is a cost-effective method for proper management. However, dry digestion of these waste streams has been restricted due to their complex structure, the presence of possible inhibitors and inappropriate operating conditions. In light of this fact, dry digestion of food waste (FW) and paper wastes (PW) was conducted at different total solid (TS) concentrations of reactor mixtures of 14%, 16%, 18% and 20% TS, corresponding to substrate to inoculum (S/I) ratio of 0.5 and 1; investigating the optimum operating conditions for effective dry digestion of these complex wastes. The highest methane yields of 402 NmlCH(4)/gVS and 229 NmlCH(4)/gVS were obtained from digestion of FW and PW, respectively at 14%TS corresponding to an S/I ratio of 0.5. Increasing the S/I ratio from 0.5 to 1 and thereby having a TS content of 20% in the reactor mixtures was unfavorable to the digestion of both substrates.

  • 149.
    Jarmander, Johan
    KTH, Skolan för bioteknologi (BIO), Bioprocessteknik (stängd 20130101).
    Improved detection and performance of surface expression from the AIDA-I autotransporter2013Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Surface expression of recombinant proteins has attracted a lot of attention due to its potential in applications such as enzyme production, vaccine delivery and bioremediation. Autotransporters have been used for surface expression of a variety of proteins, but the expression systems reported in literature have typically been inflexible and incapable of detecting proteolysis, thereby limiting surface expression yield.

    In this thesis, a modular surface expression system, utilizing dual tag detection, was therefore created. It was based on the adhesin involved in diffuse adherence (AIDA-I) autotransporter, and was here used to express the model proteins SefA and H:gm on the cell surface of Escherichia coli. Due to the dual tag detection system, proteolysed H:gm could be successfully verified on the cell surface. By optimizing cultivation conditions, surface expression yield of SefA was increased by 300 %, and proteolysis reduced by 33 %. While proteolysis could not be eliminated completely, the work presented in this thesis is a major step towards a general system for surface expression of a wide range of proteins in varied applications.

  • 150.
    Jaros, Adam Marschall
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Four carbon oxychemicals from renewable resources2012Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Butanol, butyric acid and butyraldehyde are important 4-carbon oxychemicals typically generated from petro-chemical sources. All have significant markets in the food industry either for direct use as flavorings or as chemical feedstocks for generating butyric acid and butyraldehyde derived flavour compounds. Strong consumer sentiment against the consumption of petro-chemical derived products yields a demand for butyrate and butyraldehyde generated through all-natural methods. The bacterial fermentation production of butyric acid as well as bioconversion of butanol to butyraldehyde by yeast is presented in this work as a means of producing these products naturally. This thesis demonstrates the fermentation production of butyric acid with the Gram-positive anaerobic bacteria Clostridia tyrobutyricum. The organism consumes monomeric hexoses and pentoses to generate the carboxylic acids lactate, acetate and butyrate. The fermentations undertaken in this thesis were performed with either glucose or xylose as the primary carbon source in minimal media. Butyric acid studies were performed under anaerobic conditions as batch fermentations with lag, log and stationary phase growth being monitored by the optical density of the fermentation broth. Samples were drawn throughout the fermentations and HPLC analysis was performed to determine sugar consumption and butyric acid production over time. Another element expounded in this thesis is the potential use of the economical and renewable resource hot water extracted (HWE) hemicellose as a substrate for Clostridial fermentation. HWE hemicellose is produced as a waste stream from the pulp and paper industry and is converted to fermentable xylose with the concomitant release of acetic acid from the acetyl groups on the xylan backbone. With the presence of such a high concentration of acetic acid, microbial inhibition occurs and the productivity of xylose fermentation to butyric acid is diminished with the increased lag phase. C. tyrobutyricum xylose fermentation studies were performed with synthetic media challenging the fermentation with up to 26.3 g/L acetic acid to gain an understanding of the effects of acetic acid inhibition. Once the acetic acid induced lag phase growth was characterized this work was furthered by adapting a strain of C. tyrobutyricum to 26.3 g/L acetic acid conditions and demonstrating that this pre-adaptation could drastically reduce the acetic acid induced lag phase of a batch fermentation. From this set of studies, it is noted that the presence of acetic acid in the media increases carbon efficiency of the fermentation as during stationary growth C. tyrobutyricum re-uptakes free acetic acid from the environment and converts it into butyric acid. This thesis also demonstrates the bioconversion of butanol to butyraldehyde by the methylotrophic yeast Pichia pastoris. P. pastoris were grown to high cell densities under glycerol feed and then induced to produce the endogenous alcohol oxidase (AOX) enzyme by beginning the culture on methanol consumption after a short starvation period. AOX converts short chain aliphatic alcohols to the corresponding aldehyde with the utilization of oxygen. The AOX enzyme is inhibited by the final product butyraldehyde so studies were performed utilizing alternative amine based pH buffering systems which also aid the bioconversion by binding free butyraldehyde as a Schiff-base. By binding the butyraldehyde longer bioconversions were observed. For these conversions, AOX activity was monitored with an absorbance based enzyme assay and the butanol substrate and butyraldehyde product were determined by gas chromatography.

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