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  • 101.
    Andersson, Henny
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lindmark, Johan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Jansson, Joakim
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Suhonen, Anssi
    Savonia University of Applied Sciences.
    Jääskeläinen, Ari
    Savonia University of Applied Sciences.
    Reijonen, Tero
    Savonia University of Applied Sciences.
    Laatikainen, Reino
    University of Eastern Finland.
    Heitto, Anneli
    Finnoflag.
    Hakalehto, Elias
    Finnoflag.
    Technical Output Report – Pilot A in Sweden2014Rapport (Övrigt vetenskapligt)
  • 102.
    Andersson, Jan-Erik
    et al.
    SP Sveriges Tekniska Forskningsinstitut, SP Trä.
    Nordman, Roger
    SP Sveriges Tekniska Forskningsinstitut, SP Energiteknik.
    Vikberg, Tommy
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Energy mapping in the sawmill industry with focus on drying kilns2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    The forest industry stands for approximately 11 % of Sweden’s total export. However, the forest industry is energy intensive. In 2008, sawmill industry alone consumed almost 8,7 TWh of energy, corresponding to 5 % of the Swedish industries total energy consumption. Out of their total consumption, 2200 GWh was electric power, 194 GWh heating oil , 4229 GWh bio-fuel, 574 GWh district heating, and other fuels such as diesel 1503 GWh [1].The project ”EESI- Energy Efficiency in the Sawmill Industry” was started in the spring of 2010 with the aim of demonstrating the possibilities to reduce the energy consumption in the sawmill industry with 20 % by 2020. 16 sawmill corporations and 14 equipment suppliers has joined the project which is carried out in two phases of which the first phase was carried out during 2010 and 2011. EESI has now reached half time and the first energy-saving implementations have been completed at the participating sawmills.This paper presents the energy-mapping, measurements and modelling performed by the participating sawmills during the first phase of the project [2, 3]. The average energy consumption per sawn cubic metre of boards varied between approximately 300 to 500 kWh/m3. Out of this, the electricity consumption was on average 85 kWh/m3, bio-fuel 290 kWh/m3 and diesel 1.8 l/m3.However, the main concern from sawmills regarding energy consumption was the wood drying process. The striking results from the preliminary measurements were the large variation in energy consumption even with similar drying kilns. This was especially apparent for the heat consumption in kiln dryers which could vary as much as 50 % for the same dimension of spruce planks.The results from the first phase of the project resulted in a large number of actions in order to reduce the energy consumption which are now being implemented or have already been completed. Examples of those actions are: simplified management system adapted to sawmills, weighing of packages for more accurate wood drying, reduced speed or intermittent operation of the air circulating fans in batch kilns and moisture content measurements of bio-fuel.References[1] Statistiska centralbyrån (SCB), 2013, Industrins årliga energianvändning 2011, Slutliga uppgifter, EN23SM1301, ISSN 1654-367X. (In Swedish). [2] Andersson, J-E., Lycken, A., Nordman, R., Olsson, M., Räftegård, O., and Wamming, T. State of the art – Energianvändning i den svenska sågverksindustrin. SP Rapport 2011:42, ISBN 978-91-86622-72-5. (In Swedish).[3] Andersson, J-E., Räftegård, O., Lycken, A., Olsson, M., Wamming, T., and Nordman, R. Sammanställning av energimätningar från EESI fas 1. SP Rapport 2011:41, ISBN 978-91-86622-71-8. (In Swedish).

  • 103.
    Andersson, Jan-Erik
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Nordman, Roger
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Vikberg, Tommy
    Luleå Technical University, Sweden.
    Energy mapping in the sawmill industry with focus on drying kilns2013Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The forest industry stands for approximately 11 % of Sweden’s total export. However, the forest industry is energy intensive. In 2008, sawmill industry alone consumed almost 8,7 TWh of energy, corresponding to 5 % of the Swedish industries total energy consumption. Out of their total consumption, 2200 GWh was electric power, 194 GWh heating oil , 4229 GWh bio-fuel, 574 GWh district heating, and other fuels such as diesel 1503 GWh [1].The project ”EESI- Energy Efficiency in the Sawmill Industry” was started in the spring of 2010 with the aim of demonstrating the possibilities to reduce the energy consumption in the sawmill industry with 20 % by 2020. 16 sawmill corporations and 14 equipment suppliers has joined the project which is carried out in two phases of which the first phase was carried out during 2010 and 2011. EESI has now reached half time and the first energy-saving implementations have been completed at the participating sawmills.This paper presents the energy-mapping, measurements and modelling performed by the participating sawmills during the first phase of the project [2, 3]. The average energy consumption per sawn cubic metre of boards varied between approximately 300 to 500 kWh/m3. Out of this, the electricity consumption was on average 85 kWh/m3, bio-fuel 290 kWh/m3 and diesel 1.8 l/m3.However, the main concern from sawmills regarding energy consumption was the wood drying process. The striking results from the preliminary measurements were the large variation in energy consumption even with similar drying kilns. This was especially apparent for the heat consumption in kiln dryers which could vary as much as 50 % for the same dimension of spruce planks.The results from the first phase of the project resulted in a large number of actions in order to reduce the energy consumption which are now being implemented or have already been completed. Examples of those actions are: simplified management system adapted to sawmills, weighing of packages for more accurate wood drying, reduced speed or intermittent operation of the air circulating fans in batch kilns and moisture content measurements of bio-fuel.References[1] Statistiska centralbyrån (SCB), 2013, Industrins årliga energianvändning 2011, Slutliga uppgifter, EN23SM1301, ISSN 1654-367X. (In Swedish). [2] Andersson, J-E., Lycken, A., Nordman, R., Olsson, M., Räftegård, O., and Wamming, T. State of the art – Energianvändning i den svenska sågverksindustrin. SP Rapport 2011:42, ISBN 978-91-86622-72-5. (In Swedish).[3] Andersson, J-E., Räftegård, O., Lycken, A., Olsson, M., Wamming, T., and Nordman, R. Sammanställning av energimätningar från EESI fas 1. SP Rapport 2011:41, ISBN 978-91-86622-71-8. (In Swedish).

  • 104.
    Andersson, Jim
    et al.
    Luleå University of Technology, Sweden.
    Lundgren, Joakim
    Luleå University of Technology, Sweden.
    Malek, Laura
    Lund University, Sweden.
    Hultegren, Christian
    Lund University, Sweden.
    Pettersson, Karin
    Chalmers University of Technology, Gothenburg, Sweden.
    Wetterlund, Elisabeth
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    System studies on biofuel production via integrated biomass gasification2013Rapport (Övrigt vetenskapligt)
    Abstract [en]

    A large number of national and international techno-economic studies on industrially integrated gasifiers for production of biofuels have been published during the recent years. These studies comprise different types of gasifiers (fluidized bed, indirect and entrained flow) integrated in different industries for the production of various types of chemicals and transportation fuels (SNG, FT-products, methanol, DME etc.) The results are often used for techno-economic comparisons between different biorefinery concepts. One relatively common observation is that even if the applied technology and the produced biofuel are the same, the results of the techno-economic studies may differ significantly.

    The main objective of this project has been to perform a comprehensive review of publications regarding industrially integrated biomass gasifiers for motor fuel production. The purposes have been to identify and highlight the main reasons why similar studies differ considerably and to prepare a basis for “fair” techno-economic comparisons. Another objective has been to identify possible lack of industrial integration studies that may be of interest to carry out in a second phase of the project.

    Around 40 national and international reports and articles have been analysed and reviewed. The majority of the studies concern gasifiers installed in chemical pulp and paper mills where black liquor gasification is the dominating technology. District heating systems are also well represented. Only a few studies have been found with mechanical pulp and paper mills, steel industries and the oil refineries as case basis. Other industries have rarely, or not at all, been considered for industrial integration studies. Surprisingly, no studies regarding integration of biomass gasification neither in saw mills nor in wood pellet production industry have been found.

    There are several reasons why the results of the reviewed techno-economic studies vary. Some examples are that different system boundaries have been set and that different technical and economic assumptions have been made, product yields and energy efficiencies may be calculated using different methods etc. For obvious reasons, the studies are not made in the same year, which means that different monetary exchange rates and indices have been applied. It is therefore very difficult, and sometimes even impossible, to compare the technical as well as the economic results from the different studies. When technical evaluations are to be carried out, there is no general method for how to set the system boundaries and no right or wrong way to calculate the system efficiencies as long as the boundaries and methods are transparent and clearly described. This also means that it becomes fruitless to compare efficiencies between different concepts unless the comparison is done on an exactly equal basis.

    However, even on an equal basis, a comparison is not a straight forward process. For example, calculated efficiencies may be based on the marginal supply, which then become very dependent on how the industries exploit their resources before the integration. The resulting efficiencies are therefore very site-dependent. Increasing the system boundaries to include all in- and outgoing energy carriers from the main industry, as well as the integrated gasification plant (i.e. total plant mass and energy balance), would inflict the same site-dependency problem. The resulting system efficiency is therefore a measure of the potential improvement that a specific industry could achieve by integrating a biomass gasification concept.

    When estimating the overall system efficiency of industrial biorefinery concepts that include multiple types of product flows and energy sources, the authors of this report encourage the use of electrical equivalents as a measure of the overall system efficiency. This should be done in order to take the energy quality of different energy carriers into concern.

    In the published economic evaluations, it has been found that there is a large number of studies containing both integration and production cost estimates. However, the number of references for the cost data is rather limited. The majority of these have also been published by the same group of people and use the same or similar background information. The information in these references is based on quotes and estimates, which is good, however none of these are publically available and therefore difficult to value with respect to content and accuracy.

    It has further been found that the variance in the operational costs is quite significant. Something that is particularly true for biomass costs, which have a high variance. This may be explained by natural variations in the quality of biomass used, but also to the different markets studied and the dates when the studies were performed. It may be seen from the specific investment costs that there is a significant spread in the data. It may also be seen that the differences in capital employed and process yields will result in quite large variations in the production cost of the synthetic fuels. On a general note, the studies performed are considering future plants and in some cases assumes technology development. It is therefore relevant to question the use of today’s prices of utilities and feedstock’s. It is believed that it would be more representative to perform some kind of scenario analysis using different parameters resulting in different cost assumptions to better exemplify possible futures.

    Due to the surprising lack of reports and articles regarding integration of biomass gasifiers in sawmills, it would be of great interest to carry out such a study. Also larger scale wood pellet production plants could be of interest as a potential gasification based biorefinery.

  • 105. Andersson, K
    et al.
    Gülich, S
    KTH, Tidigare Institutioner (före 2005), Biokemi och biokemisk teknologi.
    Hämäläinen, M
    Nygren, P A
    KTH, Tidigare Institutioner (före 2005), Biokemi och biokemisk teknologi.
    Hober, Sophia
    KTH, Tidigare Institutioner (före 2005), Biokemi och biokemisk teknologi.
    Malmqvist, M
    Kinetic characterization of the interaction of the Z-fragment of protein A with mouse-IgG3 in a volume in chemical space.1999Ingår i: Proteins: Structure, Function, and Bioinformatics, ISSN 0887-3585, E-ISSN 1097-0134, Vol. 37, nr 3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The kinetic rate parameters for the interaction between a single domain analogue of staphylococcal protein A (Z) and a mouse-IgG3 monoclonal antibody (MAb) were measured in Hepes buffer with different chemical additives. Five buffer ingredients (pH, NaCl, DMSO, EDTA, and KSCN) were varied simultaneously in 16 experiments following a statistical experimental plan. The 16 buffers thus spanned a volume in chemical space. A mathematical model, using data from the buffer composition, was developed and used to predict apparent kinetic parameters in five new buffers within the spanned volume. Association and dissociation parameters were measured in the new buffers, and these agreed with the predicted values, indicating that the model was valid within the spanned volume. The pattern of variation of the kinetic parameters in relation to buffer composition was different for association and dissociation, such that pH influenced both association and dissociation and NaCl influenced only dissociation. This indicated that the recognition mechanism (association) and the stability of the formed complex (dissociation) involve different binding forces, which can be further investigated by kinetic studies in systematically varied buffers.

  • 106.
    Andersson, Klara
    KTH, Skolan för bioteknologi (BIO).
    Development of a shake flask method suitable for effective screening of Escherichia coli expression constructs2011Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Screening av nya rekombinanta proteiner som ska användas till läkemedel sker oftast i batch-odling. Men själva odlingen av proteinläkemedlet sker sedan under fed-batch förhållanden. Dessa två typer av odling är olika och då cellerna växer olika kan detta leda till att fel, eller den inte mest lämpade kandidaten väljs. Därför vore det önskvärt att ta fram en fed-batch liknande metod i skakkolvar. Biosilta har tagit fram en metod där ett enzym bryter ned stärkelse till glukos som påminner om fed-batch. Denna metod har testats och undersökts i detta examensarbete. Det har visat sig att cellerna som växer under dessa förhållanden är begränsade på glukos men producerar stora mängder ättiksyra under den senare fasen av odlingen och att pH varierar mycket. Systemet bygger mycket på att en booster-tablett tillsätts, vad denna tablett innehåller är okänt. Men om tabletten inte tillsätts slutar cellerna att växa, detta tyder på att det finns någon mer begränsning än glukos. Det visade sig även att protein produktionen blev mycket lägre än vid odling i batch-fas. Det skulle av anledning av ovanstående inte vara bra att använda sig av EnBase som en screening metod.

  • 107.
    Andersson Schönn, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Promoter regulation: designing cells for biotechnological applications2016Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The filamentous cyanobacteria Nostoc punctiforme ATCC 29133 is a model species fordevelopment of sustainable production methods of numerous compounds. One of its uniquefeatures is the anaerobic environment of the strains nitrogen fixing heterocyst cells. To be ableto properly utilize this environment, more knowledge regarding what regulates cell specificexpression is required. In this study, three motifs of the NsiR I promoter of Anabaena sp.PCC 7120 was studied in this system utilizing YFP-fluorescence as a reporter to determinetheir impact on spatial expression pattern. Investigations were performed on immobilizedcells with the use of confocal microscopy and results point towards sigma factor regulation.

  • 108.
    Andersson Schönn, Mikael
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Borg, Malin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Bunpuckdee, Benja
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Gioeli, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Holdar, Karl
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning.
    Odlingsmedium: Att ersätta fetalt kalvserum med ett kemiskt definierat substitut2014Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    SammanfattningProjektgrupp 14-X5 avser med denna rapport att ge avdelningen Bioreagens på Thermo Fisher Scientific ett underlag för att på sikt kunna byta ut fetalt kalvserum (FCS) mot ett kemiskt definierat suplement vid odling av mushybridomceller för produktion av monoklonala antikroppar. Thermo Fisher Scientific är ett världsomspännande bioteknikföretag som utvecklar blodtestsystem som stöd för klinisk diagnos och uppföljning av allergier, astma och autoimmuna sjukdomar.

    Fetalt kalvserum är en tillsats i många odlingsmedier som ofta är nödvändig för att cellerna ska växa. Det finns dock många problem med FCS. Det är en biprodukt av köttindustrin och produceras på ett etiskt tveksamt sätt, variation mellan olika batcher förekommer och då det är en animalisk produkt finns en risk för kontamination av bland annat bakterier, virus och prioner. Av dessa anledningar vill man byta ut FCS mot ett kemiskt definierat, serumfritt supplement. Vi har utrett vilka ämnen eller grupper av ämnen som har störst potential att vara bra substitut för FCS, samt rangordnat dessa. Genom våra artikelstudier har vi kommit fram till att man kan dela in alternativen i tre grupper: lipider, tillväxtfaktorer och små biomolekyler. Bland lipiderna är det linol- och oljesyra som i flera artiklar har visats ha god effekt på både celltillväxt och antikroppsproduktion. Kolesterol har även visats ha positiva effekter. Tillväxtfaktorerna som har valts är epidermal growth factor (EGF), fibroblast growth factor (FGF), interleukin-2 (IL-2) och interleukin-6 (IL-6). Dessa har främst en positiv effekt på cellernas antikroppsproduktion. Bland de små biomolekyler som har valts ut finns en mängd olika ämnen som på olika sätt kan bidra till att skapa en bra miljö för hybridomceller i ett serumfritt medium.

    För att få en klarare bild av de olika förslagen har de jämförts. Vi menar att de ämnen som är komponenter i det basala mediet Ham F-12 bör prioriteras då det används som standard vid odling av en bred grupp av celltyper. Denna grupp inkluderar linolsyra, putrescin, tymidin, hypoxantin samt liponsyra. Därefter anser vi att återstående lipider (oljesyra och kolesterol) ska prioriteras då de har visats kunna öka både hybridomcellers tillväxt och antikroppsproduktion i ett serumfritt medium. Tillväxtfaktorer, som främst ökar antikroppsproduktionen hos cellerna  och i vissa fall även deras livslängd placerar vi på tredje plats i vår rangordning. Övriga ämnen i gruppen “Små biomolekyler” (paraaminobensoesyra och glutation) prioriterar vi sist då de inte är komponenter i Ham F-12 och de inte explicit visats påverka celltillväxten ellerantikroppsproduktionen, men har identifierats i det serumfria mediet IBL media III.

  • 109.
    Andersson, Simon
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för miljö- och livsvetenskaper.
    Pellet production of Sicklebush, Pigeon Pea, and Pine in Zambia: Pilot Study and Full Scale Tests to Evaluate Pellet Quality and Press Configurations2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    More deaths are caused every year by indoor air pollution than malaria, HIV/AIDS and tuberculosis combined. Cooking with traditional fuels such as charcoal and fuelwood with poor ventilation causes the single most important environmental health risk factor worldwide. It also contributes to environmental issues such as deforestation as traditional biomass fuels and cooking stoves are inefficient and requires large quantities of wood. This is especially critical in Africa where the largest regional population growth in the world is expected to occur.

    A solution to these issues was realized through fuel pellets and modern cooking stoves by Emerging Cooking Solutions, a company started by two Swedes and based in Zambia. The production of fuel pellets in Zambia is dependent on pine sawdust from small sawmills and is a declining source of raw material. However, other sources of biomass are available in Zambia such as pigeon pea stalk, an agricultural waste product, and sicklebush, an invasive tree species. If these species are viable for pelletization, the production of pellets can increase while reducing issues with sicklebush and promoting cultivation of pigeon pea. The aim of this work is to evaluate if pigeon pea stalk and sicklebush are viable to pelletize in Zambia and how the press is affected by the different raw materials.

    A pilot study is done at Karlstad University with a single unit press, hardness tester and soxhlet extractor to evaluate how the material constituents correlate to friction in the press channel and hardness of the pellets. The results of the pilot study provide support for full scale tests done in a pellet plant in Zambia. The normal production of pellets from pine sawdust is used as quality and production reference for the tests with pigeon pea stalk, sicklebush, and different mixes of the raw materials. The properties used to evaluate the quality of the pellets are hardness, durability, moisture content, bulk density, and fines. The press configuration is evaluated by logging the electricity consumption by the press motor, calculating the power and specific energy consumption from the logs, and observations during the tests.

    The results show that sicklebush, and mixes of sicklebush with pigeon pea stalk can produce pellets with better quality than the reference pine pellets. An interesting composition is a mix of 80% pigeon pea and 20% sicklebush that produces pellets with the best quality of all the tests. However, pellets produced from sicklebush and pigeon pea show a larger variation in hardness as compared to the reference pellets from pine sawdust. Mixing pigeon pea with pine reduces these variations but reduces the hardness of the pellets below the reference. The press struggles to process sicklebush and pigeon pea stalk with fluctuating power consumption that causes the motor to trip. The inhomogeneity of the materials in sicklebush and pigeon pea are identified to cause the issues in the press. Production improvements are discussed to facilitate the production of pigeon pea stalk and sicklebush pellets.

  • 110.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Land, Carl Johan
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Kuttuva Rajarao, Gunaratna
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Biological nutrient removal by individual and mixed strain biofilmsManuskript (Övrigt vetenskapligt)
  • 111.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Land, Carl Johan
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Kuttuva Rajarao, Gunaratna
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Characterization of extracellular polymeric substances from denitrifying organism Comamonas denitrificans2009Ingår i: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 82, nr 3, s. 535-543Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Extracellular polymeric substances (EPS) play an important role in the formation and activity of biofilms in wastewater treatment (WWT). The EPS of the denitrifying biomarker Comamonas denitrificans strain 110, produced in different culture media and growth modes, were characterized. The EPS mainly contained protein (3-37%), nucleic acids (9-50%), and carbohydrates (3-21%). The extracellular DNA was found to be important for initial biofilm formation since biofilm, but not planktonic growth, was inhibited in the presence of DNase. The polysaccharide fraction appeared to consist of at least two distinct polymers, one branched fraction (A) made up of glucose and mannose with a molecular weight around 100 kDa. The other fraction (B) was larger and consisted of ribose, mannose, glucose, rhamnose, arabinose, galactose, and N-acetylglucosamine. Fraction B polysaccharides were mainly found in capsular EPS which was the dominant type in biofilms and agar-grown colonies. Fraction A was abundant in the released EPS, the dominant type in planktonic cultures. Biofilm and agar-grown EPS displayed similar overall properties while planktonic EPS showed clear compositional disparity. This study presents results on the physiology of a key WWT organism, which may be useful in the future development of improved biofilm techniques for WWT purposes.

  • 112.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Rajarao, Gunaratna Kuttuva
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Persistence and competition of denitrifying biofilms subjected to a natural wastewater floraManuskript (Övrigt vetenskapligt)
  • 113.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Kuttuva Rajarao, Gunaratna
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Land, Carl Johan
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Biofilm formation and interactions of bacterial strains found in wastewater treatment systems2008Ingår i: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 283, nr 1, s. 83-90Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biofilm formation and adherence properties of 13 bacterial strains commonly found in wastewater treatment systems were studied in pure and mixed cultures using a crystal violet microtiter plate assay. Four different culture media were used, wastewater, acetate medium, glucose medium and diluted nutrient broth. The medium composition strongly affected biofilm formation. All strains were able to form pure culture biofilms within 24 h in at least one of the tested culture media and three strains were able to form biofilm in all four culture media, namely Acinetobacter calcoaceticus ATCC 23055, Comamonas denitrificans 123 and Pseudomonas aeruginosa MBL 0199. The adherence properties assessed were initial adherence, cell surface hydrophobicity, and production of amyloid fibers and extracellular polymeric substances. The growth of dual-strain biofilms showed that five organisms formed biofilm with all 13 strains while seven formed no or only weak biofilm when cocultured. In dual-strain cultures, strains with different properties were able to complement each other, giving synergistic effects. Strongest biofilm formation was observed when a mixture of all 13 bacteria were grown together. These results on attachment and biofilm formation can serve as a tool for the design of tailored systems for the degradation of municipal and industrial wastewater.

  • 114.
    Andersson, Sofia
    et al.
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Nilsson, Mirja
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Dalhammar, Gunnel
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Kuttuva Rajarao, Gunaratna
    KTH, Skolan för bioteknologi (BIO), Miljömikrobiologi.
    Assessment of carrier materials for biofilm formation and denitrification2008Ingår i: Vatten, ISSN 0042-2886, Vol. 64, s. 201-207Artikel i tidskrift (Refereegranskat)
  • 115.
    Andrade, Jorge
    et al.
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Berglund, Lisa
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Uhlén, Mathias
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Odeberg, Jacob
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Using Grid Technology for Computationally Intensive Applied Bioinformatics Analyses2006Ingår i: In Silico Biology, ISSN 1386-6338, Vol. 6, nr 6, s. 495-504Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For several applications and algorithms used in applied bioinformatics, a bottle neck in terms of computational time may arise when scaled up to facilitate analyses of large datasets and databases. Re-codification, algorithm modification or sacrifices in sensitivity and accuracy may be necessary to accommodate for limited computational capacity of single work stations. Grid computing offers an alternative model for solving massive computational problems by parallel execution of existing algorithms and software implementations. We present the implementation of a Grid-aware model for solving computationally intensive bioinformatic analyses exemplified by a blastp sliding window algorithm for whole proteome sequence similarity analysis, and evaluate the performance in comparison with a local cluster and a single workstation. Our strategy involves temporary installations of the BLAST executable and databases on remote nodes at submission, accommodating for dynamic Grid environments as it avoids the need of predefined runtime environments (preinstalled software and databases at specific Grid-nodes). Importantly, the implementation is generic where the BLAST executable can be replaced by other software tools to facilitate analyses suitable for parallelisation. This model should be of general interest in applied bioinformatics. Scripts and procedures are freely available from the authors.

  • 116.
    Andraous, Johnny I.
    et al.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Claus, Michael J
    Department of Agricultural Engineering, Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Lindemann, Deirdre J.
    Department of Chemistry, Michigan State University.
    Effect of liquefaction enzymes on methanol concentration of distilled fruit spirits2004Ingår i: American Journal of Enology and Viticulture, ISSN 0002-9254, E-ISSN 1943-7749, Vol. 55, nr 2, s. 199-201Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Liquefaction enzymes are often used during fermentation of fruit mashes to improve the yield of ethanol and the ability to pump the mash. The liquefaction enzymes hydrolyze pectin, but in addition to the desired pectin hydrolysis activity, the enzymes also have pectinesterase activity which hydrolyzes the methyl ester in pectin resulting in methanol formation. Fermentations of various apple varieties and Bartlett pears were conducted using liquefaction enzymes. The resulting distilled products contained concentrations of methanol above the legal limit of 280 mg/100 mL of 40% ethanol, with the observed methanol concentrations in a range between 320 and 656 mg/100 mL of 40% ethanol. In contrast to the undesired increase in methanol concentration, the enzymes provide only a marginal increase in ethanol yield. The results indicate that liquefaction enzymes should be used with caution for pomace fruit and that methanol monitoring should be implemented if these enzymes are used for commercial products.

  • 117.
    Anfelt, Josefine
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Metabolic engineering strategies to increase n-butanol production from cyanobacteria2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The development of sustainable replacements for fossil fuels has been spurred by concerns over global warming effects. Biofuels are typically produced through fermentation of edible crops, or forest or agricultural residues requiring cost-intensive pretreatment. An alternative is to use photosynthetic cyanobacteria to directly convert CO2 and sunlight into fuel. In this thesis, the cyanobacterium Synechocystis sp. PCC 6803 was genetically engineered to produce the biofuel n­-butanol. Several metabolic engineering strategies were explored with the aim to increase butanol titers and tolerance.

    In papers I-II, different driving forces for n-butanol production were evaluated. Expression of a phosphoketolase increased acetyl-CoA levels and subsequently butanol titers. Attempts to increase the NADH pool further improved titers to 100 mg/L in four days.

    In paper III, enzymes were co-localized onto a scaffold to aid intermediate channeling. The scaffold was tested on a farnesene and polyhydroxybutyrate (PHB) pathway in yeast and in E. coli, respectively, and could be extended to cyanobacteria. Enzyme co-localization increased farnesene titers by 120%. Additionally, fusion of scaffold-recognizing proteins to the enzymes improved farnesene and PHB production by 20% and 300%, respectively, even in the absence of scaffold.

    In paper IV, the gene repression technology CRISPRi was implemented in Synechocystis to enable parallel repression of multiple genes. CRISPRi allowed 50-95% repression of four genes simultaneously. The method will be valuable for repression of competing pathways to butanol synthesis.

    Butanol becomes toxic at high concentrations, impeding growth and thus limiting titers. In papers V-VI, butanol tolerance was increased by overexpressing a heat shock protein or a stress-related sigma factor.

    Taken together, this thesis demonstrates several strategies to improve butanol production from cyanobacteria. The strategies could ultimately be combined to increase titers further.

  • 118.
    Anfelt, Josefine
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Kaczmarzyk, Danuta
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Shabestary, Kiyan
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Renberg, Björn
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Rockberg, Johan
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Nielsen, Jens
    Uhlén, Mathias
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. Tech Univ Denmark.
    Hudson, Elton P.
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Genetic and nutrient modulation of acetyl-CoA levels in Synechocystis for n-butanol production2015Ingår i: Microbial Cell Factories, ISSN 1475-2859, E-ISSN 1475-2859, Vol. 14, artikel-id 167Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: There is a strong interest in using photosynthetic cyanobacteria as production hosts for biofuels and chemicals. Recent work has shown the benefit of pathway engineering, enzyme tolerance, and co-factor usage for improving yields of fermentation products. Results: An n-butanol pathway was inserted into a Synechocystis mutant deficient in polyhydroxybutyrate synthesis. We found that nitrogen starvation increased specific butanol productivity up to threefold, but cessation of cell growth limited total n-butanol titers. Metabolite profiling showed that acetyl-CoA increased twofold during nitrogen starvation. Introduction of a phosphoketolase increased acetyl-CoA levels sixfold at nitrogen replete conditions and increased butanol titers from 22 to 37 mg/L at day 8. Flux balance analysis of photoautotrophic metabolism showed that a Calvin-Benson-Bassham-Phosphoketolase pathway had higher theoretical butanol productivity than CBB-Embden-Meyerhof-Parnas and a reduced butanol ATP demand. Conclusion: These results demonstrate that phosphoketolase overexpression and modulation of nitrogen levels are two attractive routes toward increased production of acetyl-CoA derived products in cyanobacteria and could be implemented with complementary metabolic engineering strategies.

  • 119.
    Anfelt, Josefine
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Shabestary, Kiyan
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Hudson, Elton P.
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Complementary effects of ATP, acetyl-CoA and NADH driving forces increase butanol production in Synechocystis sp. PCC 6803Manuskript (preprint) (Övrigt vetenskapligt)
  • 120.
    Angleby, Helen
    KTH, Skolan för bioteknologi (BIO).
    Analysis of domestic dog mitochondrial DNA sequence variation for forensic investigations2005Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The first method for DNA analysis in forensics was presented in 1985. Since then, the introduction of the polymerase chain reaction (PCR) has rendered possible the analysis of small amounts of DNA and automated sequencing and fragment analysis techniques have facilitated the analyses. In most cases short tandemly repeated regions (STRs) of nuclear DNA are analysed in forensic investigations, but all samples cannot be successfully analysed using this method. For samples containing minute amounts of DNA or degraded DNA, such as shed hairs, analysis of mitochondrial DNA (mtDNA) is generally more successful due to the presence of thousands of copies of mtDNA molecules per cell.

    In Sweden, ~40 % of all households have cats or dogs. With ~9 million humans shedding ~100 scalp hairs per day, and ~1.6 million cats and ~1 million dogs shedding hairs it is not surprising that shed hairs are one of the most common biological evidence found at crime scenes. However, the match probability for domestic dog mtDNA analysis has only been investigated in a few minor studies. Furthermore, although breed –sequence correlations of the noncoding mtDNA control region (CR) have been analysed in a few studies, showing limited correlations, no largescale studies have been performed previously. Thus, there have not been any comprehensive studies of forensic informativity of dog mtDNA. In the two papers presented in this thesis we have tried to lay a foundation for forensic use of analysis of domestic dog mtDNA. In the first paper, CR sequences were analysed and the exclusion capacity was investigated for a number of different populations. This is also the first comprehensive study of the correlation between mtDNA CR type and breed, type, and geographic origin of domestic dogs. Since the exclusion capacity for analysis of domestic dog CR sequences is relatively low, it was investigated in the second paper to what extent the discrimination power is improved by analysis of coding sequence. The exclusion capacity improved considerably when 3,000 base pairs of coding sequences where analysed in addition to CR sequences. This study will hopefully work as a basis for future development of analysis of dog mtDNA for forensic purposes.

  • 121.
    Angleby, Helen
    et al.
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Oskarsson, Mattias
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Pang, Junfeng
    Zhang, Ya-ping
    Leitner, Thomas
    Braham, Caitlyn
    Arvestad, Lars
    KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsbiologi, CB. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Lundeberg, Joakim
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Webb, Kristen M.
    Savolainen, Peter
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Forensic Informativity of similar to 3000bp of Coding Sequence of Domestic Dog mtDNA2014Ingår i: Journal of Forensic Sciences, ISSN 0022-1198, E-ISSN 1556-4029, Vol. 59, nr 4, s. 898-908Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The discriminatory power of the noncoding control region (CR) of domestic dog mitochondrial DNA alone is relatively low. The extent to which the discriminatory power could be increased by analyzing additional highly variable coding regions of the mitochondrial genome (mtGenome) was therefore investigated. Genetic variability across the mtGenome was evaluated by phylogenetic analysis, and the three most variable similar to 1kb coding regions identified. We then sampled 100 Swedish dogs to represent breeds in accordance with their frequency in the Swedish population. A previously published dataset of 59 dog mtGenomes collected in the United States was also analyzed. Inclusion of the three coding regions increased the exclusion capacity considerably for the Swedish sample, from 0.920 for the CR alone to 0.964 for all four regions. The number of mtDNA types among all 159 dogs increased from 41 to 72, the four most frequent CR haplotypes being resolved into 22 different haplotypes.

  • 122.
    Angleby, Helen
    et al.
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Savolainen, Peter
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Forensic informativity of domestic dog mtDNA control region sequences2005Ingår i: Forensic Science International, ISSN 0379-0738, E-ISSN 1872-6283, Vol. 154, nr 03-feb, s. 99-110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have analysed the genetic information to be obtained from analysis of mitochondrial DNA (mtDNA) in domestic dogs studying the exclusion capacity in different populations and the correlation between mtDNA types and breeds or types of dogs. The exclusion capacities for a 573 bp sequence of the mitochondrial control region was between 0.86 and 0.95 for dogs in Sweden, the UK, Germany, Japan and China. The direct correlation between mtDNA type and breed, type of dog, and geographical origin of breed was generally low, but in some cases certain mtDNA types were overrepresented in one breed, and for wider groupings such as morphologically similar breeds, some mtDNA types were in many cases found in a distinct group of breeds, often originating from the same geographic region. This type of information may be used as an indication of the breed and, with some degree of probability, to include or exclude certain breeds from being the source of evidence materials.

  • 123.
    Antonopoulou, Io
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Development of biocatalytic processes for selective antioxidant production2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Feruloyl esterases (FAEs, EC 3.1.1.73) represent a subclass of carboxylic acid esterases that under normal conditions catalyze the hydrolysis of the ester bond between hydroxycinnamic acids (ferulic acid, sinapic acid, caffeic acid, p-coumaric acid) and sugar residues in plant cell walls. Based on their specificity towards monoferulates and diferulates, substitutions on the phenolic ring and on their amino acid sequence identity, they have been classified into four types (A-D) while phylogenetic analysis has resulted in classification into thirteen subfamilies (SF1-13). Under low water content, these enzymes are able to catalyze the esterification of hydroxycinnamic acids or the transesterification of their esters (donor) with alcohols or sugars (acceptor) resulting in compounds with modified lipophilicity, having a great potential for use in the tailor-made modification of natural antioxidants for cosmetic, cosmeceutical and pharmaceutical industries. The work described in this thesis focused on the selection,characterization and application of FAEs for the synthesis of bioactive esters with antioxidant activity in non-conventional media. The basis of the current classification systems was investigated in relation with the enzymes’ synthetic and hydrolytic abilities while the developed processes were evaluated for their efficiency and sustainability.

    Paper I was dedicated to the screening and evaluation of the synthetic abilities of 28 fungal FAEs using acceptors of different lipophilicity at fixed conditions in detergentless microemulsions. It was revealed that FAEs classified in phylogenetic subfamilies related to acetyl xylan esterases (SF5 and 6) showed increased transesterification rates and selectivity. In general, FAEs showed preference on more hydrophilic alcohol acceptors and in descending order to glycerol > 1-butanol > prenol. Homology modeling and small molecule docking simulations were employed as tools for the identification of a potential relationship between the predicted surface and active site properties of selected FAEs and the transesterification selectivity.

    Papers II- IV focused on the characterization of eight promising FAEs and the optimization of reaction conditions for the synthesis of two bioactive esters (prenyl ferulate and L-arabinose ferulate) in detergentless microemulsions. The effect of the medium composition, the donor and acceptor concentration, the enzyme load, the pH, the temperature and the agitation on the transesterification yield and selectivity were investigated. It was observed that the acceptor concentration and enzyme load were crucial parameters for selectivity. Fae125 (Type A, SF5) iiexhibited highest prenyl ferulate yield (81.1%) and selectivity (4.685) converting 98.5% of VFA to products after optimization at 60 mM VFA, 1.5 M prenol, 0.04 mg FAE mL-1, 40oC, 24 h, 53.4:43.4:3.2 v/v/v n-hexane: t-butanol: 100 mM MOPS-NaOH pH 8.0. On the other hand, FaeA1 (Type A, SF5) showed highest L-arabinose ferulate yield (52.2 %) and selectivity (1.120) at 80 mM VFA, 55 mM L-arabinose, 0.02 mg FAE mL-1, 50oC, 8 h, 19.8: 74.7: 5.5 v/v/v n-hexane: t-butanol: 100 mM MOPS-NaOH pH 8.0.

    In paper V, the effect of reaction media on the enzyme stability and transesterification yield and selectivity was studied in different solvents for the synthesis of two bioactive esters: prenyl ferulate and L-arabinose ferulate. The best performing enzyme (Fae125) was used in the optimization of reaction conditions in the best solvent (n-hexane) via response surface methodology. Both bioconversions were best described by a two-factor interaction model while optimal conditions were determined as the ones resulting in highest yield and selectivity.Highest prenyl ferulate yield (87.5%) and selectivity (7.616) were observed at 18.56 mM prenol mM-1VFA, 0.04 mg FAE mL-1, 24.5 oC, 24.5 h, 91.8: 8.2 v/v n-hexane: 100 mM sodium acetate pH 4.7. Highest L-arabinose ferulate yield (56.2%) and selectivity (1.284) were observed at 2.96 mM L-arabinose mM-1VFA, 0.02 mg FAE mL-1, 38.9 oC, 12 h, 90.5: 5.0: 4.5 v/v/v n-hexane: dimethyl sulfoxide: 100 mM sodium acetate pH 4.7. The enzyme could be reused for six consecutive reaction cycles maintaining 66.6% of its initial synthetic activity. The developed bioconversions showed exceptional biocatalyst productivities (> 300 g product g-1FAE) and the waste production was within the range of pharmaceutical processes.

    Paper VI focused on the investigation of the basis of the type A classification of a well-studied FAE from Aspergillus niger(AnFaeA) by comparing its activity towards methyl and arabinose hydroxycinnamic acid esters. For this purpose, L-arabinose ferulateand caffeate were synthesized enzymatically. kcat/Kmratios revealed that AnFaeA hydrolyzed arabinose ferulate 1600 times and arabinose caffeate 6.5 times more efficiently than methyl esters. This study demonstrated that short alkyl chain hydroxycinnamate esters which are used nowadays for FAE classification can lead to activity misclassification, while L-arabinose esters could potentially substitute synthetic esters in classification describing more adequately the enzyme specificitiesin the natural environment.

  • 124.
    Antonopoulou, Io
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Dilokpimol, Adiphol
    Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University.
    Iancu, Laura
    Dupont Industrial Biosciences.
    Mäkelä, Miia R.
    Department of Microbiology, University of Helsink.
    Varriale, Simona
    Department of Chemical Sciences, University of Naples “Federico II”.
    Cerullo, Gabriella
    Department of Chemical Sciences, University of Naples “Federico II”.
    Hüttner, Silvia
    Department of Biology and Biological Engineering, Division of Industrial Biotechnology, Chalmers University of Technology.
    Uthoff, Stefan
    Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster.
    Jütten, Peter
    Taros Chemicals GmbH & Co KG.
    Piechot, Alexander
    Taros Chemicals GmbH & Co KG.
    Steinbüchel, Alexander
    nstitut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster.
    Olsson, Lisbeth
    Department of Biology and Biological Engineering, Division of Industrial Biotechnology, Chalmers University of Technology.
    Faraco, Vincenza
    Department of Chemical Sciences, University of Naples “Federico II”.
    Hildén, Kristiina
    Department of Microbiology, University of Helsinki.
    de Vries, Ronald
    Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    The Synthetic Potential of Fungal Feruloyl Esterases: A Correlation with Current Classification Systems and Predicted Structural Properties2018Ingår i: Catalysts, ISSN 2073-4344, Vol. 8, nr 6, artikel-id 242Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Twenty-eight fungal feruloyl esterases (FAEs) were evaluated for their synthetic abilities in a ternary system of n-hexane: t-butanol: 100 mM MOPS-NaOH pH 6.0 forming detergentless microemulsions. Five main derivatives were synthesized, namely prenyl ferulate, prenyl caffeate, butyl ferulate, glyceryl ferulate, and l-arabinose ferulate, offering, in general, higher yields when more hydrophilic alcohol substitutions were used. Acetyl xylan esterase-related FAEs belonging to phylogenetic subfamilies (SF) 5 and 6 showed increased synthetic yields among tested enzymes. In particular, it was shown that FAEs belonging to SF6 generally transesterified aliphatic alcohols more efficiently while SF5 members preferred bulkier l-arabinose. Predicted surface properties and structural characteristics were correlated with the synthetic potential of selected tannase-related, acetyl-xylan-related, and lipase-related FAEs (SF1-2, -6, -7 members) based on homology modeling and small molecular docking simulations.

  • 125.
    Antonopoulou, Io
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Hunt, Cameron
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Cerullo, Gabriella
    Department of Chemical Sciences, University of Naples "Federico II".
    Varriale, Simona
    Department of Chemical Sciences, University of Naples “Federico II”.
    Gerogianni, Alexandra
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Faraco, Vincenza
    Department of Chemical Sciences, University of Naples "Federico II".
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Tailoring the specificity of the type C feruloyl esterase FoFaeC from Fusarium oxysporum towards methyl sinapate by rational redesign based on small molecule docking simulations2018Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 13, nr 5, artikel-id e0198127Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The type C feruloyl esterase FoFaeC from Fusarium oxysporum is a newly discovered enzyme with high potential for use in the hydrolysis of lignocellulosic biomass but it shows low activity towards sinapates. In this work, small molecule docking simulations were employed in order to identify important residues for the binding of the four model methyl esters of hydroxycinnamic acids, methyl ferulate/caffeate/sinapate/p-coumarate, to the predicted structure of FoFaeC. Subsequently rational redesign was applied to the enzyme’ active site in order to improve its specificity towards methyl sinapate. A double mutation (F230H/T202V) was considered to provide hydrophobic environment for stabilization of the methoxy substitution on sinapate and a larger binding pocket. Five mutant clones and the wild type were produced in Pichia pastoris and biochemically characterized. All clones showed improved activity, substrate affinity, catalytic efficiency and turnover rate compared to the wild type against methyl sinapate, with clone P13 showing a 5-fold improvement in catalytic efficiency. Although the affinity of all mutant clones was improved against the four model substrates, the catalytic efficiency and turnover rate decreased for the substrates containing a hydroxyl substitution.

  • 126.
    Antonopoulou, Io
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Iancu, Laura
    Dupont Industrial Biosciences, Wageningen, the Netherlands.
    Jütten, Peter
    Taros Chemicals GmbH & Co KG, Dortmund, Germany.
    Piechot, Alexander
    Taros Chemicals GmbH & Co KG, Dortmund, Germany.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Optimized Enzymatic Synthesis of Feruloyl Derivatives Catalyzed by Three Novel Feruloyl Esterases from Talaromyces wortmannii in Detergentless Microemulsions2018Ingår i: Computational and Structural Biotechnology Journal, ISSN 2001-0370, s. 361-369Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three novel feruloyl esterases (Fae125, Fae7262 and Fae68) from Talaromyces wortmanniioverexpressed in the C1 platform were evaluated for the transesterification of vinyl ferulatewith two acceptors of different size and lipophilicity (prenol and L-arabinose) in detergentless microemulsions. The effect of reaction conditions such as the microemulsion composition, the substrate concentration, the enzyme load, the pH, the temperature and the agitation were investigated. The type A Fae125 belonging to the subfamily 5 (SF5) of phylogenetic classification showed highest yields for the synthesis of both products after optimization of reaction conditions: 81.8% for prenyl ferulate and 33.0% for L-arabinose ferulate. After optimization, an 8-fold increase in the yield and a 12-fold increase in selectivity were achieved for the synthesis of prenyl ferulate.

  • 127.
    Antonopoulou, Io
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Iancu, Laura
    Dupont Industrial Biosciences.
    Jütten, Peter
    Taros Chemicals GmbH & Co KG.
    Piechot, Alexander
    Taros Chemicals GmbH & Co KG.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Screening of novel feruloyl esterases from Talaromyces wortmannii for the development of efficient and sustainable syntheses of feruloyl derivatives2019Ingår i: Enzyme and microbial technology, ISSN 0141-0229, E-ISSN 1879-0909, Vol. 120, s. 124-135Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The feruloyl esterases Fae125, Fae7262 and Fae68 from Talaromyces wortmannii were screened in 10 different solvent: buffer systems in terms of residual hydrolytic activity and of the ability for the transesterification of vinyl ferulate with prenol or L-arabinose. Among the tested enzymes, the acetyl xylan-related Fae125 belonging to the phylogenetic subfamily 5 showed highest yield and selectivity for both products in alkane: buffer systems (n-hexane or n-octane). Response surface methodology, based on a 5-level and 6-factor central composite design, revealed that the substrate molar ratio and the water content were the most significant variables for the bioconversion yield and selectivity. The effect of agitation, the possibility of DMSO addition and the increase of donor concentration were investigated. After optimization, competitive transesterification yields were obtained for prenyl ferulate (87.5-92.6%) and L-arabinose ferulate (56.2-61.7%) at reduced reaction times (≤ 24 h) resulting in good productivities (> 1 g/L/h, >300 kg product/kg FAE). The enzyme could be recycled for six consecutive cycles retaining 66.6% of the synthetic activity and 100% of the selectivity.

  • 128.
    Antonopoulou, Io
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Leonov, Laura
    DuPont Industrial Biosciences.
    Jûtten, Peter
    Taros Chemicals GmbH & Co.
    Cerullo, Gabriella
    Department of Chemical Sciences, University of Naples "Federico II".
    Faraco, Vincenza
    Department of Chemical Sciences, University of Naples "Federico II".
    Papadopoulou, Adamantia
    Institute of Biosciences and Applications NCSR "Demokritos," Laboratory of Cell Proliferation and Aging.
    Kletsas, Dimitris
    Institute of Biosciences and Applications NCSR "Demokritos," Laboratory of Cell Proliferation and Aging.
    Ralli, Marianna
    Korres Natural Products.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Correction to: Optimized synthesis of novel prenyl ferulate performed by feruloyl esterases from Myceliophthora thermophila in microemulsions2018Ingår i: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 102, nr 1, s. 511-511Artikel i tidskrift (Refereegranskat)
  • 129.
    Antonopoulou, Io
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Leonov, Laura
    DuPont Industrial Biosciences.
    Jûtten, Peter
    Taros Chemicals GmbH & Co.
    Cerullo, Gabriella
    Department of Chemical Sciences, University of Naples "Federico II".
    Faraco, Vincenza
    Department of Chemical Sciences, University of Naples "Federico II".
    Papadopoulou, Adamantia
    Institute of Biosciences and Applications NCSR "Demokritos," Laboratory of Cell Proliferation and Aging.
    Kletsas, Dimitris
    Institute of Biosciences and Applications NCSR "Demokritos," Laboratory of Cell Proliferation and Aging.
    Ralli, Marianna
    Korres Natural Products.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Optimized synthesis of novel prenyl ferulate performed by feruloyl esterases from Myceliophthora thermophila in microemulsions2017Ingår i: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 101, nr 8, s. 3213-3226Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Five feruloyl esterases (FAEs; EC 3.1.1.73), FaeA1, FaeA2, FaeB1, and FaeB2 from Myceliophthora thermophila C1 and MtFae1a from M. thermophila ATCC 42464, were tested for their ability to catalyze the transesterification of vinyl ferulate (VFA) with prenol in detergentless microemulsions. Reaction conditions were optimized investigating parameters such as the medium composition, the substrate concentration, the enzyme load, the pH, the temperature, and agitation. FaeB2 offered the highest transesterification yield (71.5 ± 0.2%) after 24 h of incubation at 30 °C using 60 mM VFA, 1 M prenol, and 0.02 mg FAE/mL in a mixture comprising of 53.4:43.4:3.2 v/v/v n-hexane:t-butanol:100 mM MOPS-NaOH, pH 6.0. At these conditions, the competitive side hydrolysis of VFA was 4.7-fold minimized. The ability of prenyl ferulate (PFA) and its corresponding ferulic acid (FA) to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals was significant and similar (IC50 423.39 μM for PFA, 329.9 μM for FA). PFA was not cytotoxic at 0.8–100 μM (IC50 220.23 μM) and reduced intracellular reactive oxygen species (ROS) in human skin fibroblasts at concentrations ranging between 4 and 20 μM as determined with the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay.

  • 130.
    Antonopoulou, Io
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Papadopoulou, Adamantia
    Laboratory of Cell Proliferation & Ageing, Institute of Biosciences & Applications NCSR “Demokritos”, T. Patriarchou Grigoriou & Neapoleos.
    Iancu, Laura
    DuPont Industrial Biosciences.
    Cerullo, Gabriella
    Department of Chemical Sciences, University of Naples "Federico II".
    Ralli, Marianna
    Korres Natural Products.
    Jûtten, Peter
    Taros Chemicals GmbH & Co.
    Piechot, Alexander
    Taros Chemicals GmbH & Co.
    Faraco, Vincenza
    Department of Chemical Sciences, University of Naples "Federico II".
    Kletsas, Dimitris
    Institute of Biosciences and Applications NCSR "Demokritos," Laboratory of Cell Proliferation and Aging.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Optimization of enzymatic synthesis of l-arabinose ferulate catalyzed by feruloyl esterases from Myceliophthora thermophila in detergentless microemulsions and assessment of its antioxidant and cytotoxicity activities2018Ingår i: Process Biochemistry, ISSN 1359-5113, E-ISSN 1873-3298, Vol. 65, s. 100-108Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The feruloyl esterases FaeA1, FaeA2, FaeB1, FaeB2 from Myceliophthora thermophila C1 and MtFae1a from M. thermophila ATCC 42464 were used as biocatalysts for the transesterification of vinyl ferulate (VFA) with l-arabinose in detergentless microemulsions. The effect of parameters such as the microemulsion composition, the substrate concentration, the enzyme load, the pH, the temperature and the agitation was investigated. FaeA1 offered the highest transesterification yield (52.2 ± 4.3%) after 8 h of incubation at 50 °C using 80 mM VFA, 55 mM l-arabinose and 0.02 mg FAE mL−1 in a mixture comprising of 19.8: 74.7: 5.5 v/v/v n-hexane: t-butanol: 100 mM MOPS-NaOH pH 8.0. The ability of l-arabinose ferulate (AFA) to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals was significant (IC50 386.5 μM). AFA was not cytotoxic even at high concentrations (1 mM) however was found to be pro-oxidant at concentrations higher than 20 μM when the antioxidant activity was determined with the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay in human skin fibroblasts.

  • 131.
    Antonopoulou, Io
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Spanopoulos, Athanasios
    Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str, Zografou Campus, Athens, Greece.
    Matsakas, Leonidas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Single cell oil and ethanol production by the oleaginous yeast Trichosporon fermentans utilizing dried sweet sorghum stalks2020Ingår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 146, s. 1609-1617Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The ability of the oleaginous yeast Trichosporon fermentans to efficiently produce lipids when cultivated in dried sweet sorghum was evaluated. First, lipid production was evaluated in synthetic media mimicking the composition of sweet sorghum stalks and optimized based on the nitrogen source and C: N ratio. Under optimum conditions, the lipid production reached 3.66 g/L with 21.91% w/w lipid content by using a mixture of sucrose, glucose and fructose and peptone at C: N ratio 160. Cultivation on pre-saccharified sweet sorghum stalks offered 1.97 g/L, while it was found that sweet sorghum stalks can support yeast growth and lipid production without the need for external nitrogen source addition. At an attempt to increase the carbon source concentration for optimizing lipid production, the Crabtree effect was observed in T. fermentans. To this end, the yeast was evaluated for its potential to produce ethanol under anaerobic conditions in synthetic media and sweet sorghum. The ethanol concentration at 100 g/L glucose was 40.31 g/L, while utilizing sweet sorghum by adding a distinct saccharification step and external nitrogen source offered ethanol concentration equal to 23.5 g/L. To the authors’ knowledge, this is the first time that the Crabtree effect is observed in T. fermentans.

  • 132.
    Antonopoulou, Io
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Varriale, Simona
    Department of Chemical Sciences, University of Naples "Federico II".
    Topakas, Evangelos
    National Technical University of Athens, School of Chemical Engineering, National Technical University of Athens, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Faraco, Voncenza
    Department of Chemical Sciences, University of Naples "Federico II".
    Enzymatic synthesis of bioactive compounds with high potential for cosmeceutical application2016Ingår i: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 100, nr 15, s. 6519-6543Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cosmeceuticals are cosmetic products containing biologically active ingredients purporting to offer a pharmaceutical therapeutic benefit. The active ingredients can be extracted and purified from natural sources (botanicals, herbal extracts, or animals) but can also be obtained biotechnologically by fermentation and cell cultures or by enzymatic synthesis and modification of natural compounds. A cosmeceutical ingredient should possess an attractive property such as anti-oxidant, anti-inflammatory, skin whitening, anti-aging, anti-wrinkling, or photoprotective activity, among others. During the past years, there has been an increased interest on the enzymatic synthesis of bioactive esters and glycosides based on (trans)esterification, (trans)glycosylation, or oxidation reactions. Natural bioactive compounds with exceptional theurapeutic properties and low toxicity may offer a new insight into the design and development of potent and beneficial cosmetics. This review gives an overview of the enzymatic modifications which are performed currently for the synthesis of products with attractive properties for the cosmeceutical industry

  • 133.
    Antti, Lena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Heating and drying wood using microwave power1999Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The potentials for moisture flux in wood during microwave heating have been investigated experimentally and theoretically. The experiments were performed in three different kinds of microwave applicators. A computer model based on the finite difference method was developed to describe and predict the heat and mass transfer. The main conclusions are that microwave energy of 2.45 GHz frequency makes it possible to heat and dry pine and spruce 20 - 30 times faster than with conventional methods without any deterioration in drying quality. Some hardwoods are dried in approximately half the time compared to the softwoods. The drying method evokes unique results either with diminishing colour changes or with possibilities to create such during drying. However, to avoid unevenness in the electromagnetic field distribution and considering the limitation in power penetration depth the drying should be performed on line where wood components continuously are fed through a microwave field.

  • 134.
    Antti, Lena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Microwave drying of hardwood: moisture measurements using CT-scanning1992Ingår i: Understanding the wood drying process: a synthesis of theory and practice : [proceedings of the] 3rd IUFRO conference on wood drying, August 18-21, 1992, Vienna, Austria, Wien: IUFRO , 1992Konferensbidrag (Refereegranskat)
  • 135.
    Antti, Lena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Microwave drying of hardwood: Potentials for moisture flux1993Ingår i: Microwave and high frequency 1993: International congress : Papers, abstracts and programme., Göteborg: Institut für Volksmusikforschung und Ethnomusikologie, Universität für Musik und darstellende Kunst Wien, 1993, s. E2-Konferensbidrag (Övrigt vetenskapligt)
  • 136.
    Antti, Lena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Microwave drying of hardwood: simultaneous measurements of pressure, temperature, and weight reduction1992Ingår i: Forest products journal, ISSN 0015-7473, Vol. 42, nr 6, s. 49-54Artikel i tidskrift (Refereegranskat)
  • 137.
    Antti, Lena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Microwave drying of pine and spruce1995Ingår i: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 53, nr 5, s. 333-338Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    microwave energy consumption from 365 to 760 kWh/m 3. Internal wood temperatures up to 140°C were used. Internal vapour pressure in the wood could rise to about 20 kPa without checking. Maximal drying rates of 0.20 to 0.45% moisture content per minute are possible to obtain when drying above fiber saturation (fsp). Below fsp the feasible drying rates ranged from 0.10 to 0.20% moisture content per minute. Spruce dried approximately 1.6 times faster than pine. No conditioning of the wood was necessary since the wood was free of stresses. The wood was free of checks but colour changes occured in the interior of some specimens.

  • 138.
    Antti, Lena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Några inverkande faktorer vid mikrovågstorkning av lövträ1991Rapport (Övrigt vetenskapligt)
  • 139.
    Antti, Lena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Värmeövergång mellan trä och luft vid luftcirkulationstorkning: Klimat- och materialparametrars inverkan på värmeövergångstalet vid torkning av furu1989Rapport (Övrigt vetenskapligt)
  • 140.
    Antti, Lena
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Finell, M.
    Arshadi, M.
    Lestander, T.
    Microwave drying of sawdust: effect on biofuel pellet2010Ingår i: Proceedings, 11th International IUFRO Wood Drying Conference: in Skellefteå, Sweden, January 18 - 22, 2010 ... the theme of the conference was "Recent Advances in the Field of Wood Drying" / [ed] Tom Morén; Lena Antti; Margot Sehlstedt-Persson, Luleå: Luleå tekniska universitet, 2010, s. 313-319Konferensbidrag (Refereegranskat)
  • 141.
    Antti, Lena
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Finell, Michael
    Swedish University of Agricultural Sciences.
    Arshadi, Mehrdad
    Swedish University of Agricultural Sciences.
    Lestander, Torbjörn A.
    Swedish University of Agricultural Sciences.
    Effects of microwave drying on biomass fatty acid composition and fuel pellet quality2011Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 6, nr 1-2, s. 34-40Artikel i tidskrift (Refereegranskat)
  • 142.
    Antti, Lena
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Hansson, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Equalization of moisture in pre-dried pinewood using microwave power2010Ingår i: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 6, nr 2, s. 53-59Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Commonly, during air-circulation kiln drying moisture gradients within wood cross-sections are developed, i.e. the surfaces become drier than the interior. To minimize these gradients a conditioning step subsequent to the drying is needed. The aim with this study was to investigate the possibility to use microwave power for equalization of moisture within pinewood boards after air-circulation kiln drying to the average moisture content 0,14. Two dimensions of pinewood were tested; thickness 50 and 63 mm, in two different plants, generating 5 and 12 kW microwave power respectively. Results show that microwave energy give rise to a fast and advantageous moisture equalization within the wood. The higher microwave power density the faster heating and moisture redistribution in these wood dimensions. Required time for heating and redistribution of moisture was found to be as short as 3 minutes at the power density 500 kW/m3. In addition, split-tests indicate decreased or elimination of gap after microwave treatment in the investigated specimens.

  • 143.
    Antti, Lena
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Hansson, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Microwave treatment of resinous wood2006Ingår i: Wood structure and properties '06: [proceedings of the 5th IUFRO Symposium Wood Structure and Properties '06 held on September 3-6, 2006 in Sliač - Sielnica, Slovakia] / [ed] R. Lagana; S. Kurjatko; J. Kudela, Zvolen, Slovakia: Arbora Publishers , 2006, s. 435-437Konferensbidrag (Refereegranskat)
    Abstract [en]

    The output from conventional air-circulation drying of wood is not always satisfying; some individual wood boards often contain somewhat higher moisture content (MC) than the target MC. Higher MC in some pine wood boards after conventional drying could origin from the fact that these contain higher amounts of resin, which may delay or to some extent prevent the moisture flux. It could be the reason to problems in further wood production processes, as for example in gluing processes. The aim of this study was to determine whether or not microwave (MW) heating could be a suitable method to condition these components. Another aim was to investigate if and how migration of resin appears during MW treatment. The study includes experimental tests where determination of both MC and resin content (RC) were carried out before and after MW treatment. Results from the tests show that the RC and the MC are interacting; it means that volumes with high RC also withhold increased amount of moisture; these volumes are often found within boards that origin from the root end of logs. It is possible to dry/condition these planks to reach the target MC within minutes or hours, depending on wood thickness, using MW power. By exposing resinous wood to microwaves, migration of resin takes place from the interior towards the wood surfaces, especially longitudinally through the wood towards the butt ends. It seems to be possible to redistribute RC and MC in wood by exposing only parts of a plank to microwaves.

  • 144.
    Antti, Lena
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Hansson, Lars
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Redistribution of moisture in pre-dried pinewood using microwave power: a preliminary study2010Ingår i: Proceedings, 11th International IUFRO Wood Drying Conference: [... in Skellefteå, Sweden, January 18 - 22, 2010 ... the theme of the conference was "Recent Advances in the Field of Wood Drying"] / [ed] Tom Morén; Lena Antti; Margot Sehlstedt-Persson, Luleå: Luleå tekniska universitet, 2010, s. 234-238Konferensbidrag (Refereegranskat)
    Abstract [en]

    Commonly, during air-circulation kiln drying moisture gradients within wood cross-sections are developed, i.e. thesurfaces become drier than the interior. To minimize these gradients a conditioning step subsequent to the drying isneeded. The aim with this study was to investigate the possibility to use microwave power for redistribution ofmoisture within pinewood planks after air-circulation kiln drying to the average moisture content 0,14. Twodimensions of pinewood were tested; thickness 50 and 63 mm, in two different plants, generating 5 and 12 kWmicrowave power respectively. Results show that microwave energy give rise to a fast and advantageous moistureredistribution i.e. equalization of moisture content within the wood. The higher microwave power density the fasterheating and moisture equalization in these wood dimensions. Required time for heating and redistribution ofmoisture was found to be as short as 3 minutes at the power density 500 kW/m3. In addition, split-tests indicatedecreased or almost no gap in the investigated specimens.

  • 145.
    Antti, Lena
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Jönsson, Anette
    LTU.
    Nilsson, Magnus
    LTU.
    The effect of drying method on the mechanical properties of wood: Comparisons between conventional kiln and microwave dried Scots pine2001Ingår i: Proceedings of the 3rd European Cost E15 Workshop on Wood Drying: with the theme Softwood drying to meets needs of further processing and specific end-uses : 11-13 June 2001 at Scandic Hotel Kalastajatorppa, Helsinki, Finland, Espoo: VTT Building and Transport , 2001, s. 21:1-21:9Konferensbidrag (Refereegranskat)
  • 146.
    Antti, Lena
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Perre, P.
    ENGREF - Laboratory of Forest Sciences.
    A microwave applicator for on line wood drying: Temperature and moisture distribution in wood1999Ingår i: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 33, nr 2, s. 123-138Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An especially designed open microwave applicator was analysed using wood as the material to be heated and dried. The idea was to develop an on line microwave construction consisting of several small open applicators, each fed by a small standard magnetron (for example 1.4 kW main power). The process was analysed by measuring the wood temperature during heating using an IR-camera and detecting the moisture distribution during drying by CT-scanning. Pine and birch wood samples were used in the experiments, mainly 40 mm in thickness. The experiments show that the power distribution differs between dry wood and moist wood. The analysis of the temperature fields captured by the IR-camera during the first minutes allows a rather accurate determination of the MW power. Consequently, the drying proceeds unevenly in the wood specimens, especially in the longitudinal direction. The dimensions of the applicator and its relation to the wood dimension are very important. However, the wood was not destroyed, the temperature and moisture gradients did not affect the wood in terms of checks or deformations. The drying rate in different positions of the specimen varied between 0.30 and 0.80 percentage moisture content/min. The uneven energy, meaning temperature and field distribution, is to be compensated in the future by a moving wood load and by alternating the position of each applicator in a larger scale microwave pilot plant.

  • 147.
    Antti, Lena
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Torgovnikov, Grigori
    Microwave heating of wood1995Ingår i: Fifth international conference on microwave and high frequency heating, 17-21 September 1995, Cambridge: Cambridge University Press, 1995, s. E3.1-3.4Konferensbidrag (Refereegranskat)
  • 148.
    Antti, Lena
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Zhao, H.
    Turner, I.
    An Investigation of the Heating of Wood in an Industrial Microwave Applicator: Theory and Practice2000Ingår i: 6th international IUFRO wood drying conference on wood drying research and technology for sustainable forestry beyond 2000, Marcel Dekker Incorporated , 2000Konferensbidrag (Refereegranskat)
  • 149.
    Antti, Lena
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Zhao, H.
    Turner, I.
    Investigation of the heating of wood in an industrial microwave applicator: theory and practice2000Ingår i: Drying Technology, ISSN 0737-3937, E-ISSN 1532-2300, Vol. 18, nr 8, s. 1665-1676Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work a comprehensive set of experimental results are used as an excellent means to understand the coupling that exists between the material and the electromagnetic fields in a specific industrial microwave applicator. The analysis of the infrared images allows an accurate map of the power and temperature distributions within the wood sample to be determined. This map, together with the simulation results of a previously developed computational electromagnetic model, can provide a detailed understanding of the design features of the microwave applicator. In particular, it is possible to locate the occurrence of localised hot spots and to examine the uniformity of the heat distribution throughout the sample. The simulation results provide the evolution of the electromagnetic fields inside the entire applicator and the sample. The coupling of theory and practice is the best way to proceed in optimising the design and for proposing new applicator geometry that can heat the material more effectively.

  • 150.
    Arabi, R.
    et al.
    Department of Chemical Engineering, Isfahan University of Technology.
    Bemanian, S.
    Department of Chemical Engineering, Isfahan University of Technology.
    Taherzadeh, Mohammad J
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Rapid biodegradation of methyl tert-butyl ether (MTBE) by pure bacterial cultures2007Ingår i: Iranian Journal of Chemistry and Chemical Engineering, ISSN 1021-9986, Vol. 26, nr 1, s. 1-7Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two pure bacterial strains capable of rapid degrading methyl tert-butyl ether (MTBE) were isolated from an industrial wastewater treatment plant, identified and characterized. These strains are able to grow on MTBE as the sole carbon and energy souces and completely mineralize it to the biomass and carbon dioxide. The strains were identified as Bacillus cereus and Klebsiella terrigena. Both strains are able to grow in the presence of 48 gl-1 MTBE in water, which is almost the maximum concentration of MTBE in the water. They were able to completely degrade 10 gl-1 MTBE in less than a day. The specific degradation rate of MTBE at optimum conditions were 5.89 and 5.78 g(MTBE) g(cells)-1 h-1 for B. cereus and K. terrigena, respectively. The biomass yield was 0.085 and 0.076 gg-1, respectively. The cultivations were carried out successfully at 25, 30 and 37 °C, while they showed the best performance at 37 °C. Neither of the strains was able to grow and degrade MTBE anaerobically.

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