Browsing NTNU Open by Author "Ertesvåg, Helga"
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Alginate Biosynthesis Factories in Pseudomonas fluorescens : Localization and Correlation with Alginate Production Level
Maleki, Susan; Almaas, Eivind; Zotchev, Sergey; Valla, Svein; Ertesvåg, Helga (Journal article; Peer reviewed, 2016)Pseudomonas fluorescens is able to produce the medically and industrially important exopolysaccharide alginate. The proteins involved in alginate biosynthesis and secretion form a multiprotein complex spanning the inner ... -
Alginate-modifying enzymes: Biological roles and biotechnological uses
Ertesvåg, Helga (Journal article; Peer reviewed, 2015)Alginate denotes a group of industrially important 1-4-linked biopolymers composed of the C-5-epimers β-D-mannuronic acid (M) and α-L-guluronic acid (G). The polysaccharide is manufactured from brown algae where it constitutes ... -
ATP-Dependent Citrate Lyase and Glycerol 3-Phosphate Dehydrogenase in Aurantiochytrium T66: An Attempted In Vivo Analysis and Heterologous Expression
Jakobsen, Margit Ertresvåg (Master thesis, 2019)Thraustochytrider er industrielt interessante mikroorganismer på grunn av deres evne til å produsere store mengder lipider, spesielt omega-3 fettsyren dokosaheksaensyre (DHA). Metabolismen til disse organismene er ikke ... -
Construction and characterization of broad-host-range reporter plasmid suitable for on-line analysis of bacterial host responses related to recombinant protein production
Gawin, Agnieszka; Peebo, Karl; Sebastian, Hans; Ertesvåg, Helga; Irla, Marta Katarzyna; Neubauer, Peter; Brautaset, Trygve (Journal article; Peer reviewed, 2019)Background Bacteria are widely used as hosts for recombinant protein production due to their rapid growth, simple media requirement and ability to produce high yields of correctly folded proteins. Overproduction of ... -
Draft genome sequence of the docosahexaenoic acid producing thraustochytrid Aurantiochytrium sp. T66
Liu, Bin; Ertesvåg, Helga; Aasen, Inga Marie; Vadstein, Olav; Brautaset, Trygve; Heggeset, Tonje Marita Bjerkan (Journal article; Peer reviewed, 2016)Thraustochytrids are unicellular, marine protists, and there is a growing industrial interest in these organisms, particularly because some species, including strains belonging to the genus Aurantiochytrium, accumulate ... -
Effekten av å aktivere en genklynge med potensiell kitin syntase aktivitet i Erwinia carotovora
Hagen, Kjersti Næss (Master thesis, 2011)Kitin er en langkjedet, nitrogenholdig polymer som er bygget opp av N-acetyl-glukosamin-enheter (GlcNAc), og finnes i blant annet det ytre skallet til leddyr, og i celleveggen til sopp. Biosyntese av kitin er katalysert ... -
Functional characterization of three Azotobacter chroococcum alginate-modifying enzymes related to the Azotobacter vinelandii AlgE mannuronan C-5-epimerase family
Gawin, Agnieszka Maria; Tietze, Lisa; Aarstad, Olav Andreas; Aachmann, Finn Lillelund; Brautaset, Trygve; Ertesvåg, Helga (Peer reviewed; Journal article, 2020)Bacterial alginate initially consists of 1-4-linked beta-D-mannuronic acid residues (M) which can be later epimerized to alpha-L-guluronic acid (G). The family of AlgE mannuronan C-5-epimerases from Azotobacter vinelandii ... -
Green foam-based methods of mineral and ion separation
Jain, Garima; Havskjold, Håkon; Dhar, Priyanka; Ertesvåg, Helga; Chernyshova, Irina; Kota, Hanumantha Rao (Chapter, 2020)We discuss an important gap in the literature on progress toward the development of green (microbial-derived) reagents in conventional (froth flotation) and emerging (foam flotation)separation methods. For comparison, we ... -
Guluronic acid content as a factor affecting turbidity removal potential of alginate
Moral, Cigdem Kivilcimdan; Ertesvåg, Helga; Sanin, F. Dilek (Journal article; Peer reviewed, 2016)Alginates are natural polymers composed of mannuronic and guluronic acid residues. They are currently extracted from brown algae; however, alginate can also be synthesized by some species of Azotobacter and Pseudomonas. ... -
Identification of a New Phosphatase Enzyme Potentially Involved in the Sugar Phosphate Stress Response in Pseudomonas fluorescens
Maleki, Susan; Hrudikova, Radka; Zotchev, Sergey; Ertesvåg, Helga (Journal article; Peer reviewed, 2017)The alginate-producing bacterium Pseudomonas fluorescens utilizes the Entner-Doudoroff (ED) and pentose phosphate (PP) pathways to metabolize fructose, since the upper part of its Embden-Meyerhof-Parnas pathway is defective. ... -
Identification of genes affecting alginate biosynthesis in Pseudomonas fluorescens by screening a transposon insertion library.
Ertesvåg, Helga; Sletta, Håvard; Senneset, Mona; Sun, Yi-Qian; Klinkenberg, Geir; Konradsen, Therese Aursand; Ellingsen, Trond E; Valla, Svein (Journal article; Peer reviewed, 2017)BACKGROUND: Polysaccharides often are necessary components of bacterial biofilms and capsules. Production of these biopolymers constitutes a drain on key components in the central carbon metabolism, but so far little is ... -
Identification of Regulatory Genes and Metabolic Processes Important for Alginate Biosynthesis in Azotobacter vinelandii by Screening of a Transposon Insertion Mutant Library
Mærk, Mali; Jakobsen, Øyvind Mejdell; Sletta, Håvard; Klinkenberg, Geir; Tøndervik, Anne; Ellingsen, Trond Erling; Valla, Svein; Ertesvåg, Helga (Journal article; Peer reviewed, 2020)Azotobacter vinelandii produces the biopolymer alginate, which has a wide range of industrial and pharmaceutical applications. A random transposon insertion mutant library was constructed from A. vinelandii ATCC12518Tc in ... -
Karakterisering av gener som påvirker biosyntesen av alginat i Azotobacter vinelandii
Haugsnes, Margit Dagsdatter (Master thesis, 2012)For å undersøke faktorer som innvirker på alginat-produksjonen til Azotobacter vinelandii har det blitt laget et mutant-bibliotek med stammen A. vinelandii ATCC 12518 som utgangspunkt. Etter screeningsforsøk med henblikk ... -
Karakterisering av gener som påvirker biosyntesen av alginat i Pseudomonas fluorescens
Selsaas, Eirik (Master thesis, 2011)Pseudomonas fluorescens har evne til å produsere store store mengder alginat. Tidligere er det laget en stamme, P. fluorescens SBW25 MS1 ΔalgC::TnKb61, hvor algD-operonet og algC er satt under kontroll av Pm-promotor. Dette ... -
Konstruksjon av vektorer for et CRISPR-Cas9 muteringssystem for Azotobacter vinelandii
Dahl, Marie Duus (Master thesis, 2019)Azotobacter vinelandii er en alginatproduserende bakterie med en viss industriell interesse. Alginat er en biopolymer benyttet i mange industrielle felt på grunn av dens geldannende egenskap. Bakteriell alginat har en annen ... -
Lipid and DHA-production in Aurantiochytrium sp. – Responses to nitrogen starvation and oxygen limitation revealed by analyses of production kinetics and global transcriptomes
Heggeset, Tonje Marita Bjerkan; Ertesvåg, Helga; Liu, Bin; Ellingsen, Trond Erling; Vadstein, Olav; Aasen, Inga Marie (Journal article; Peer reviewed, 2019)Thraustochytrids of the genera Schizochytrium and Aurantiochytrium accumulate oils rich in the essential, marine n3 fatty acid docosahexaenoic acid (DHA). DHA production in Aurantiochytrium sp T66 was studied with the aim ... -
Mannuronan C-5 Epimerases Suited for Tailoring of Specific Alginate Structures Obtained by High-Throughput Screening of an Epimerase Mutant Library
Tøndervik, Anne; Klinkenberg, Geir; Aachmann, Finn Lillelund; Svanem, Britt Iren Glærum; Ertesvåg, Helga; Ellingsen, Trond Erling; Valla, Svein; Skjåk-Bræk, Gudmund; Sletta, Håvard (Journal article; Peer reviewed, 2013)The polysaccharide alginate is produced by brown algae and some bacteria and is composed of the two monomers, β-d-mannuronic acid (M) and α-l-guluronic acid (G). The distribution and composition of M/G are important for ... -
Mapping global effects of the anti-sigma factor MucA in Pseudomonas fluorescens SBW25 through genome-scale metabolic modeling
Borgos, Sven Even F.; Bordel, Sergio; Sletta, Håvard; Ertesvåg, Helga; Jakobsen, Øyvind Mejdell; Bruheim, Per; Ellingsen, Trond Erling; Nielsen, Jens; Valla, Svein (Journal article; Peer reviewed, 2013)Background: Alginate is an industrially important polysaccharide, currently produced commercially by harvesting of marine brown sea-weeds. The polymer is also synthesized as an exo-polysaccharide by bacteria belonging to ... -
Marinobacter algicola - en ny alginatprodusent?
Heddeland Instefjord, Kamilla (Master thesis, 2013)Alginat er et polysakkarid bredt utnyttet i industrien, og består av beta-D-mannuronsyre (M) og alfa-L-guluronsyre (G). Disse monomerene er gruppert sammen i blokker av M, G eller MG. Under biosyntesen av alginat hos ... -
Method Development Progress in Genetic Engineering of Thraustochytrids
Rau, E-Ming; Ertesvåg, Helga (Peer reviewed; Journal article, 2021)Thraustochytrids are unicellular, heterotrophic marine eukaryotes. Some species are known to store surplus carbon as intracellular lipids, and these also contain the long-chain polyunsaturated fatty acid docosahexaenoic ...