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  • 251.
    Papaspyridi, Lefki-Maria
    et al.
    National Technical University of Athens.
    Aligiannis, Nektarios
    University of Athens.
    Topakas, Evangelos
    National Technical University of Athens.
    Christakopoulos, Paul
    Skaltsounis, Alexandros-Leandros
    University of Athens.
    Fokialakis, Nikolas
    University of Athens.
    Submerged fermentation of the edible mushroom Pleurotus ostreatus in a batch stirred tank bioreactor as a promising alternative for the effective production of bioactive metabolites2012Inngår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 17, nr 3, s. 2714-2724Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to investigate the potential of the submerged fermentation procedure in the production of bioactive metabolites of the common edible mushroom Pleurotus ostreatus. The biomass of the mushroom strain was produced by submerged fermentation in a batch stirred tank bioreactor and extracted by solvents of increasing polarity. The dichloromethane and methanol extract were fractioned by different techniques including Adsorption Chromatography and Fast Centrifugal Partition Chromatography (FCPC). The structures of pure compounds were elucidated with 1D/2D NMR-spectroscopic analyses, and chemical correlations combined with GC/MS and LC/MS experiments. Nineteen metabolites (e.g., fatty acids, phenolic metabolites, nucleotides and alkaloids) were isolated. Beyond the production of known metabolites, we report herein the production also of trans-3,4-dihydro-3,4,8-trihydroxynapthalen-1(2H)-one, indolo-3-carboxylic acid, 3-formylpyrrole and 4-hydroxybenzoic acid, that have pharmaceutical interest and are isolated for the first time from Pleurotus strains.This work indicates the great potential of the established bioprocess for the production of P. ostreatus mycelia with enhanced metabolic profile.

  • 252.
    Papaspyridi, Papaspyridi, Lefki Maria
    et al.
    National Technical University of Athens.
    Sinanoglou, V.J.
    Technological Educational Institution of Athens Instrumental Food Analysis Laboratory, Department of Food Technology.
    Strati, I.F.
    Technological Educational Institution of Athens Instrumental Food Analysis Laboratory, Department of Food Technology.
    Katapodis, P.
    University of Ioannina, Biotechnology Laboratory, Department of Biological Applications and Technologies.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Fatty acid profiles of Pleurotus ostreatus and Ganoderma australe grown naturally and in a batch reactor2013Inngår i: Acta alimentaria, ISSN 0139-3006, E-ISSN 1588-2535, Vol. 42, nr 3, s. 328-337Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Non-polar lipid content and fatty acid (FA) composition of the commercial edible strain of Pleurotus ostreatus and the medicinal wild strain of Ganoderma australe were determined. A comparison of the FA profile was conducted between mycelium grown under optimum bioreactor conditions and naturally occurring fruit bodies in both species. Both strains contained unsaturated FA (UFA), amounting to 55–77% of total FA content, whereas the proportion of essential FA was contributive, permitting their consideration as potential food ingredients. Bioreactor process resulted in a significant total FA content increase accompanied with a considerable effect on ratios of nutritional interest (MUFA/SFA, PUFA/SFA, oleic/linoleic).

  • 253.
    Parreiras, Lucas S.
    et al.
    University of Wisconsin.
    Breuer, Rebecca J.
    University of Wisconsin.
    Narasimhan, Ragothaman Avanasi
    University of Wisconsin.
    Higbee, Alan J.
    University of Wisconsin.
    Reau, Alex La
    University of Wisconsin.
    Tremaine, Mary T.
    University of Wisconsin.
    Qin, Li
    University of Wisconsin.
    Willis, Laura B.
    University of Wisconsin.
    Bice, Benjamin D.
    University of Wisconsin.
    Bonfert, Brandi L.
    University of Wisconsin.
    Pinhancos, Rebeca C.
    University of Wisconsin.
    Balloon, Allison J.
    University of Wisconsin.
    Uppugundla, Nirmal
    Michigan State University.
    Liu, Tongjun
    Michigan State University.
    Li, Chenlin
    Lawrence Berkeley National Laboratory.
    Tanjore, Deepti
    Lawrence Berkeley National Laboratory.
    Ong, Irene
    University of Wisconsin.
    Li, Haibo
    University of Wisconsin.
    Pohlmann, Edward L.
    University of Wisconsin.
    Serate, Jose
    University of Wisconsin.
    Withers, Sydnor T.
    University of Wisconsin.
    Simmons, Blake Alexander
    Joint BioEnergy Institute, California, Deconstruction Division, Berkeley.
    Hodge, David
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Westphall, Michael S.
    University of Wisconsin.
    Coon, Joshua J.
    University of Wisconsin.
    Sato, Trey
    University of Wisconsin.
    Engineering and two-stage evolution of a lignocellulosic hydrolysate-tolerant Saccharomyces cerevisiae strain for anaerobic fermentation of xylose from AFEX pretreated corn stover2014Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, nr 9, artikkel-id e107499Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The inability of the yeast Saccharomyces cerevisiae to ferment xylose effectively under anaerobic conditions is a major barrier to economical production of lignocellulosic biofuels. Although genetic approaches have enabled engineering of S. cerevisiae to convert xylose efficiently into ethanol in defined lab medium, few strains are able to ferment xylose from lignocellulosic hydrolysates in the absence of oxygen. This limited xylose conversion is believed to result from small molecules generated during biomass pretreatment and hydrolysis, which induce cellular stress and impair metabolism. Here, we describe the development of a xylose-fermenting S. cerevisiae strain with tolerance to a range of pretreated and hydrolyzed lignocellulose, including Ammonia Fiber Expansion (AFEX)-pretreated corn stover hydrolysate (ACSH). We genetically engineered a hydrolysate-resistant yeast strain with bacterial xylose isomerase and then applied two separate stages of aerobic and anaerobic directed evolution. The emergent S. cerevisiae strain rapidly converted xylose from lab medium and ACSH to ethanol under strict anaerobic conditions. Metabolomic, genetic and biochemical analyses suggested that a missense mutation in GRE3, which was acquired during the anaerobic evolution, contributed toward improved xylose conversion by reducing intracellular production of xylitol, an inhibitor of xylose isomerase. These results validate our combinatorial approach, which utilized phenotypic strain selection, rational engineering and directed evolution for the generation of a robust S. cerevisiae strain with the ability to ferment xylose anaerobically from ACSH.

  • 254.
    Paschos, Thomas
    et al.
    Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens.
    Xiros, Charilaos
    National Technical University of Athens, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Ethanol effect on metabolic activity of the ethalogenic fungus Fusarium oxysporum2015Inngår i: BMC Biotechnology, ISSN 1472-6750, E-ISSN 1472-6750, Vol. 15, nr 1, artikkel-id 15Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background Fusarium oxysporum is a filamentous fungus which has attracted a lot of scientific interest not only due to its ability to produce a variety of lignocellulolytic enzymes, but also because it is able to ferment both hexoses and pentoses to ethanol. Although this fungus has been studied a lot as a cell factory, regarding applications for the production of bioethanol and other high added value products, no systematic study has been performed concerning its ethanol tolerance levels. Results In aerobic conditions it was shown that both the biomass production and the specific growth rate were affected by the presence of ethanol. The maximum allowable ethanol concentration, above which cells could not grow, was predicted to be 72 g/L. Under limited aeration conditions the ethanol-producing capability of the cells was completely inhibited at 50 g/L ethanol. The lignocellulolytic enzymatic activities were affected to a lesser extent by the presence of ethanol, while the ethanol inhibitory effect appears to be more severe at elevated temperatures. Moreover, when the produced ethanol was partially removed from the broth, it led to an increase in fermenting ability of the fungus up to 22.5%. The addition of F. oxysporum’s system was shown to increase the fermentation of pretreated wheat straw by 11%, in co-fermentation with Saccharomyces cerevisiae. Conclusions The assessment of ethanol tolerance levels of F. oxysporum on aerobic growth, on lignocellulolytic activities and on fermentative performance confirmed its biotechnological potential for the production of bioethanol. The cellulolytic and xylanolytic enzymes of this fungus could be exploited within the biorefinery concept as their ethanol resistance is similar to that of the commercial enzymes broadly used in large scale fermentations and therefore, may substantially contribute to a rational design of a bioconversion process involving F. oxysporum. The SSCF experiments on liquefied wheat straw rich in hemicellulose indicated that the contribution of the metabolic system of F. oxysporum in a co-fermentation with S. cerevisiae may play a secondary role.

  • 255.
    Paschos, Thomas
    et al.
    Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens.
    Xiros, Charilaos
    National Technical University of Athens, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Simultaneous saccharification and fermentation by co-cultures of Fusarium oxysporum and Saccharomyces cerevisiae enhances ethanol production from liquefied wheat straw at high solid content2015Inngår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 76, s. 793-802Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A co-fermentation process involving Saccharomyces cerevisiae and Fusarium oxysporum was studied, using hydrothermally pretreated wheat straw as substrate. In the first step of the study, we examined liquefaction of the material in a free-fall reactor. Both the enzyme loading and the dry matter content affected severely the liquefaction efficiency. In the second step (simultaneous saccharification and fermentation (SSF) experiments), we found that the enzymatic system of F. oxysporum contributed significantly to substrate hydrolysis, while its metabolic system played a secondary role in fermentation. SSF in the presence of F. oxysporum cells and enzymes gave 62 g L−1 ethanol. In the third step of the study, a semi-consolidated bioprocess was designed in which F. oxysporum culture (submerged or solid-state) was added at the SSF stage along with S. cerevisiae. The addition of solid F. oxysporum culture increased ethanol production by 19%, leading to a final ethanol concentration of 58 g L−1. The present study proposes a semi-consolidated process combining two microorganisms for the fermentation at high solids concentration of a liquefied material using an in house free fall mixing reactor. The semi-consolidated process proposed not only increased the ethanol yields significantly, but could also lead to lower overall cost of the process by incorporating in-situ enzyme production.

  • 256.
    Passoth, Volkmar
    et al.
    Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Blomqvist, Johanna
    Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Schnürer, Johan
    Department of Microbiology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Dekkera bruxellensis and Lactobacillus vini form a stable ethanol-producing consortium in a commercial alcohol production process2007Inngår i: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 73, nr 13, s. 4354-4356Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ethanol production process of a Swedish alcohol production plant was dominated by Dekkera bruxellensis and Lactobacillus vini, with a high number of lactic acid bacteria. The product quality, process productivity, and stability were high; thus, D. bruxellensis and L. vini can be regarded as commercial ethanol production organisms.

  • 257.
    Patel, Alok
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Molecular Microbiology Laboratory, Biotechnology Department, Indian Institute of Technology Roorkee (IIT-R), Roorkee, Uttarakhand, India .
    Matsakas, Leonidas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Pruthi, Parul A
    Molecular Microbiology Laboratory, Biotechnology Department, Indian Institute of Technology Roorkee (IIT-R), Roorkee, Uttarakhand, India .
    Pruthi, Vikas
    Molecular Microbiology Laboratory, Biotechnology Department, Indian Institute of Technology Roorkee (IIT-R), Roorkee, Uttarakhand, India .
    Potential of aquatic oomycete as a novel feedstock for microbial oil grown on waste sugarcane bagasse2018Inngår i: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biodiesel production from vegetable oils is not sustainable and economical due to the food crisis worldwide. The development of a cost-effective non-edible feedstock is essential. In this study, we proposed to use aquatic oomycetes for microbial oils, which are cellulolytic fungus-like filamentous eukaryotic microorganisms, commonly known as water molds. They differ from true fungi as cellulose is present in their cell wall and chitin is absent. They show parasitic as well as saprophytic nature and have great potential to utilize decaying animal and plant debris in freshwater habitats. To study the triacylglycerol (TAG) accumulation in the aquatic oomycetes, the isolated water mold Achlya diffusa was cultivated under semi-solid-state conditions on waste sugarcane bagasse, which was compared with the cultivation in Czapek (DOX) medium. A. diffusa grown on waste sugarcane bagasse showed large lipid droplets in its cellular compartment and synthesized 124.03 ± 1.93 mg/gds cell dry weight with 50.26 ± 1.76% w/w lipid content. The cell dry weight and lipid content of this water mold decreased to 89.54 ± 1.21 mg/gds and 38.82% w/w, respectively, when cultivated on standard medium Czapek-Dox agar (CDA). For the fatty acid profile of A. diffusa grown in sugarcane bagasse and CDA, in situ transesterification (IST) and indirect transesterification (IDT) approaches were evaluated. The lipid profile of this mold revealed the presence of C12:0, C14:0, C16:0, C18:0, C18:1, C18:2, C20:0, and C21:0 fatty acids, which is similar to vegetable oils. The biodiesel properties of the lipids obtained from A. diffusa satisfied the limits as determined by international standards ASTM-D6751 and EN-14214 demonstrating its suitability as a fuel for diesel engines.

  • 258.
    Patel, Alok
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Matsakas, Leonidas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Heterotrophic cultivation of Auxenochlorella protothecoides using forest biomass as a feedstock for sustainable biodiesel production2018Inngår i: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 11, nr 1, artikkel-id 169Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background

    The aim of this work was to establish a process for the heterotrophic growth of green microalgae using forest biomass hydrolysates. To provide a carbon source for the growth of the green microalgae, two forest biomasses (Norway spruce and silver birch) were pretreated with a hybrid organosolv-steam explosion method, resulting in inhibitor-free pretreated solids with a high cellulose content of 77.9% w/w (birch) and 72% w/w (spruce). Pretreated solids were hydrolyzed using commercial cellulolytic enzymes to produce hydrolysate for the culture of algae.

    Results

    The heterotrophic growth of A. protothecoides was assessed using synthetic medium with glucose as carbon source, where the effect of sugar concentration and the carbon-to-nitrogen ratio were optimized, resulting in accumulation of lipids at 5.42 ± 0.32 g/L (64.52 ± 0.53% lipid content) after 5 days of culture on glucose at 20 g/L. The use of birch and spruce hydrolysates was favorable for the growth and lipid accumulation of the algae, resulting in lipid production of 5.65 ± 0.21 g/L (66 ± 0.33% lipid content) and 5.28 ± 0.17 g/L (63.08 ± 0.71% lipid content) when grown on birch and spruce, respectively, after only 120 h of cultivation.

    Conclusions

    To the best of our knowledge, this is the first report of using organosolv pretreated wood biomass hydrolysates for the growth and lipid production of microalgae in the literature. The pretreatment process used in this study provided high saccharification of biomass without the presence of inhibitors. Moreover, the lipid profile of this microalga showed similar contents to vegetable oils which improve the biodiesel properties.

  • 259.
    Patel, Alok
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Mikes, Fabio
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Matsakas, Leonidas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    An Overview of Current Pretreatment Methods Used to Improve Lipid Extraction from Oleaginous Microorganisms2018Inngår i: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 23, nr 7, artikkel-id 1562Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Microbial oils, obtained from oleaginous microorganisms are an emerging source of commercially valuable chemicals ranging from pharmaceuticals to the petroleum industry. In petroleum biorefineries, the microbial biomass has become a sustainable source of renewable biofuels. Biodiesel is mainly produced from oils obtained from oleaginous microorganisms involving various upstream and downstream processes, such as cultivation, harvesting, lipid extraction, and transesterification. Among them, lipid extraction is a crucial step for the process and it represents an important bottleneck for the commercial scale production of biodiesel. Lipids are synthesized in the cellular compartment of oleaginous microorganisms in the form of lipid droplets, so it is necessary to disrupt the cells prior to lipid extraction in order to improve the extraction yields. Various mechanical, chemical and physicochemical pretreatment methods are employed to disintegrate the cellular membrane of oleaginous microorganisms. The objective of the present review article is to evaluate the various pretreatment methods for efficient lipid extraction from the oleaginous cellular biomass available to date, as well as to discuss their advantages and disadvantages, including their effect on the lipid yield. The discussed mechanical pretreatment methods are oil expeller, bead milling, ultrasonication, microwave, high-speed and high-pressure homogenizer, laser, autoclaving, pulsed electric field, and non-mechanical methods, such as enzymatic treatment, including various emerging cell disruption techniques.

  • 260.
    Payne, Mark J.
    et al.
    Michigan State University.
    Berglund, Kris
    Raman spectroscopic studies of titanium aloxides using UV excitation1986Inngår 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. 627-631Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The use of Raman spectroscopy can be this hindered by the presence of fluorescing impurities. In this study, Raman spectra were recorded for various titanium alkoxides (ethoxide, isopropoxide, isobutoxide) as a function of concentration and laser excitation wavelength. Fluorescence can be avoided by using uv-excitation (363. 8 nm). In addition, titanium alkoxides exhibit a preresonance Raman enhancement as the excitation wavelength approaches the UV. This result is confirmed by a uv-visible absorption spectrum of the isopropoxide.

  • 261.
    Periyannan Rajeswari, Prem Kumar
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH Royal Institute of Technology.
    Jönsson, Håkan N
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Andersson Svahn, Helene
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Droplet size influences division of mammalian cell factories in droplet microfluidic cultivation2016Inngår i: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The potential of using droplet microfluidics for screening mammalian cell factories has been limited by the difficulty in achieving continuous cell division during cultivation in droplets. Here, we report the influence of droplet size on mammalian cell division and viability during cultivation in droplets. Chinese Hamster Ovary (CHO) cells, the most widely used mammalian host cells for biopharmaceuticals production were encapsulated and cultivated in 33, 180 and 320 pL droplets for 3 days. Periodic monitoring of the droplets during incubation showed that the cell divisions in 33 pL droplets stopped after 24 h, whereas continuous cell division was observed in 180 and 320 pL droplets for 72 h. The viability of the cells cultivated in the 33 pL droplets also dropped to about 50% in 72 h. In contrast, the viability of the cells in the larger droplets was above 90% even after 72 h of cultivation, making them a more suitable droplet size for 72-h cultivation. This study shows a direct correlation of microfluidic droplet size to the division and viability of mammalian cells. This highlights the importance of selecting suitable droplet size for mammalian cell factory screening assays.

  • 262.
    Phongpreecha, Thanaphong
    et al.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, USA.
    Hool, Nicholas C.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, USA.
    Stoklosa, Ryan J.
    Sustainable Biofuels and Co-Products Research Unit, Eastern Regional Research Center, USDA, ARS, 600 East Mermaid Lane, Wyndmoor, USA.
    Klett, Adam S.
    Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, USA.
    Foster, Cliff E.
    DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA.
    Bhalla, Aditya
    DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, USA.
    Holmes, Daniel
    Department of Chemistry, Michigan State University, East Lansing, USA.
    Thies, Mark C.
    Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, USA.
    Hodge, David B.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik. Department of Chemical and Biological Engineering, Montana State University, Bozeman, USA.
    Predicting lignin depolymerization yields from quantifiable properties using fractionated biorefinery lignins2017Inngår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 19, nr 21, s. 5131-5143Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lignin depolymerization to aromatic monomers with high yields and selectivity is essential for the economic feasibility of many lignin-valorization strategies within integrated biorefining processes. Importantly, the quality and properties of the lignin source play an essential role in impacting the conversion chemistry, yet this relationship between lignin properties and lignin susceptibility to depolymerization is not well established. In this study, we quantitatively demonstrate how the detrimental effect of a pretreatment process on the properties of lignins, particularly β-O-4 content, limit high yields of aromatic monomers using three lignin depolymerization approaches: thioacidolysis, hydrogenolysis, and oxidation. Through pH-based fractionation of alkali-solubilized lignin from hybrid poplar, this study demonstrates that the properties of lignin, namely β-O-4 linkages, phenolic hydroxyl groups, molecular weight, and S/G ratios exhibit strong correlations with each other even after pretreatment. Furthermore, the differences in these properties lead to discernible trends in aromatic monomer yields using the three depolymerization techniques. Based on the interdependency of alkali lignin properties and its susceptibility to depolymerization, a model for the prediction of monomer yields was developed and validated for depolymerization by quantitative thioacidolysis. These results highlight the importance of the lignin properties for their suitability for an ether-cleaving depolymerization process, since the theoretical monomer yields grows as a second order function of the β-O-4 content. Therefore, this research encourages and provides a reference tool for future studies to identify new methods for lignin-first biomass pretreatment and lignin valorization that emphasize preservation of lignin qualities, apart from focusing on optimization of reaction conditions and catalyst selection.

  • 263.
    Quershi, Nasib
    et al.
    United States Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Bioenergy Research Unit, Peoria, IL.
    Hodge, David
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Vertès, Alain
    London Business School.
    Biorefineries: Integrated Biochemical Processes for Liquid Biofuels2014Bok (Fagfellevurdert)
  • 264.
    Qureshi, Nasib
    et al.
    United States Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Bioenergy Research Unit, Peoria, IL.
    Hodge, David
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Vertès, Alain
    London Business School.
    Preface2014Annet (Annet vitenskapelig)
  • 265.
    Raghavendran, Vijayendran
    et al.
    Industrial Biotechnology Division, Department of Biology and Biological Engineering, Chalmers University of Technology.
    Nitsos, Christos
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Matsakas, Leonidas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Olsson, Lisbeth
    Industrial Biotechnology Division, Department of Biology and Biological Engineering, Chalmers University of Technology.
    A comparative study of the enzymatic hydrolysis of batch organosolv-pretreated birch and spruce biomass2018Inngår i: AMB Express, ISSN 2191-0855, E-ISSN 2191-0855, Vol. 8, nr 1, artikkel-id 114Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A shift towards a sustainable and green society is vital to reduce the negative effects of climate change associated with increased CO2 emissions. Lignocellulosic biomass is both renewable and abundant, but is recalcitrant to deconstruction. Among the methods of pretreatment available, organosolv (OS) delignifies cellulose efficiently, significantly improving its digestibility by enzymes. We have assessed the hydrolysability of the cellulose-rich solid fractions from OS-pretreated spruce and birch at 2% w/v loading (dry matter). Almost complete saccharification of birch was possible with 80 mg enzyme preparation/gsolids (12 FPU/gsolids), while the saccharification yield for spruce was only 70%, even when applying 60 FPU/gsolids. As the cellulose content is enriched by OS, the yield of glucose was higher than in their steam-exploded counterparts. The hydrolysate was a transparent liquid due to the absence of phenolics and was also free from inhibitors. OS pretreatment holds potential for use in a large-scale, closed-loop biorefinery producing fuels from the cellulose fraction and platform chemicals from the hemicellulose and lignin fractions respectively.

  • 266.
    Rasimas, J. P.
    et al.
    Michigan State University.
    Berglund, Kris
    Blanchard, G. J.
    Michigan State University.
    A molecular lock-and-key approach to detecting solution phase self-assembly: a fluorescence and absorption study of carminic acid in aqueous glucose solutions1996Inngår i: Journal of Physical Chemistry, ISSN 0022-3654, Vol. 100, nr 17, s. 7220-7229Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We introduce a novel approach to the study of complex ternary systems where a fluorescent chromophore contains a functionality that incorporates into precrystalline aggregates in concentrated solutions. We demonstrate the feasibility of this approach by using carminic acid, a fluorescent molecule possessing a pendant glycosyl moiety, in aqueous glucose solutions. We report the steady state absorption and emission response of carminic acid as well as its picosecond dynamical response. These data, taken collectively, show that saturated glucose solutions exhibit anomalous molecular scale organization and that the persistence time of this organization is significantly less than a nanosecond. Our results indicate that kinetic contributions to crystallization are expected to play an important, sometimes dominant, role in this technologically important process.

  • 267.
    Rasimas, J. P.
    et al.
    Michigan State University.
    Berglund, Kris
    Blanchard, G. J.
    Michigan State University.
    Measuring self-assembly in solution: incorporation and dynamics of a "Tailor-made impurity" in precrystalline glucose aggregates1996Inngår i: Journal of Physical Chemistry, ISSN 0022-3654, Vol. 100, nr 42, s. 17034-17040Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have studied the onset of crystallization from solution using a fluorescent probe molecule that incorporates selectively into precrystalline glucose aggregates that form in supersaturated aqueous glucose solutions. We achieve incorporation of the fluorophore into the aggregates by virtue of the fluorophore pendant glycosyl moiety and compare the rotational diffusion data for this molecule to that for the nonglycosylated, native probe molecule. This experimental approach, in conjunction with semiempirical calculations to understand the electronic response of the fluorescent probe, provides insight into the formation and size of precrystalline glucose aggregates. Our data indicate that the aggregates effectively isolate the fluorophore from the solution over a range of glucose concentrations spanning the saturation point and that the lifetime of these aggregates is on the order of a nanosecond for aggregates that include the glycosylated probe molecule. The subtle but important differences between these results and those we reported previously for carminic acid in aqueous glucose solutions point to the significant role of labile protons in mediating the formation and dynamics of precrystalline glucose aggregates.

  • 268.
    Reissig, Alexander
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi. Linköpings universitet, Tekniska högskolan.
    Evaluation of on-line cell viability and L-lactate measurements in soft sensor for mammalian cell cultures2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Increasing demand on more effective cell culture reactors has driven optimization works to increase output of products. This has led to development of soft sensors that uses mathematical formulas to increase the available information for the parameters during runs. In the project two parameters was evaluated for use in such a soft sensor, viability by measuring on-line capacitance with Aber probe and L-lactate production using BioSenz apparatus. To determine how well these could be used both were used on batch reactors measuring on a mouse-mouse B cell hybridoma culture which produced IgG1. On-line measurements were performed by probes which measured directly on the cell suspension or withdrew sterile sample from the reactor. Measuring viability gave results with low error, which can be concluded to the variation in reference cell count, but it could not be determined if measuring L-lactate production with BioSenz works in reactors of this size. More work needs to be done on other types of reactors, like fed-batch or perfusion, or lower working volumes. 

  • 269. Richau, KH
    et al.
    Kudahettige-Nilsson, Rasika
    Pujic, P
    Kudahettige, NP
    Sellstedt, A
    Structural and gene expression analyses of uptake hydrogenases and other proteins involved in nitrogenase protection in Frankia2013Inngår i: Journal of Biosciences, ISSN 0250-5991, E-ISSN 0973-7138, Vol. 38, nr 4, s. 703-713Artikkel i tidsskrift (Fagfellevurdert)
  • 270.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Broad sugar range for succinic acid fermentation2007Inngår i: Industrial Bioprocessing, ISSN 1056-7194, Vol. 29, nr 3, s. 9-Artikkel i tidsskrift (Annet vitenskapelig)