Browsing NTNU Open by Author "Aarstad, Olav Andreas"
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Alginate sequencing: Block distribution in alginates and its impact on macroscopic properties
Aarstad, Olav Andreas (Doktoravhandlinger ved NTNU, 1503-8181; 2013:26, Doctoral thesis, 2013) -
Analysis of G-Block Distributions and Their Impact on Gel Properties of in Vitro Epimerized Mannuronan
Aarstad, Olav Andreas; Strand, Berit Løkensgard; Klepp-Andersen, Lise Mari; Skjåk-Bræk, Gudmund (Journal article; Peer reviewed, 2013)This paper reports a study of the distribution and function of homopolymeric guluronic acid blocks (G-blocks) in enzymatically modified alginate. High molecular weight mannuronan was incubated with one native (AlgE6) and ... -
Bi-functional alginate oligosaccharide–polymyxin conjugates for improved treatment of multidrug-resistant gram-negative bacterial infections
Stokniene, Joana; Powell, Lydia C.; Aarstad, Olav Andreas; Aachmann, Finn Lillelund; Rye, Philip D; Hill, Katja E.; Thomas, David W.; Ferguson, Elaine L. (Peer reviewed; Journal article, 2020)The recent emergence of resistance to colistin, an antibiotic of last resort with dose-limiting toxicity, has highlighted the need for alternative approaches to combat infection. This study aimed to generate and characterise ... -
Biosynthesis and Function of Long Guluronic Acid-Blocks in Alginate Produced by Azotobacter vinelandii
Aarstad, Olav Andreas; Stanisci, Annalucia; Sætrom, Gerd Inger; Tøndervik, Anne; Sletta, Håvard; Aachmann, Finn Lillelund; Skjåk-Bræk, Gudmund (Journal article; Peer reviewed, 2019)With the present accessibility of algal raw material, microbial alginates as a source for strong gelling material are evaluated as an alternative for advanced applications. Recently, we have shown that alginate from algal ... -
Changes in food quality attributes of Saccharina latissima following pre-treatments, frozen storage and subsequent thawing
Stevant, Pierrick Francois Denis; Aachmann, Finn Lillelund; Arlov, Øystein; Nordtvedt, Tom Ståle; Sarno, Antonio; Aarstad, Olav Andreas; Klau, Leesa Jane; Rustad, Turid; Sæther, Maren; Rebours, Celine (Journal article; Peer reviewed, 2024)Changes in relevant quality attributes for the food industry were monitored in Saccharina latissima following pre-treatment (PT), freezing and thawing. The evaluation included the monitoring of qualitative indicators (dry ... -
Characterization of three Macroalgae: Saccharina latissima, Alaria esculenta and Palmaria palmata - Effect of Different Harvesting Conditions
Fische, Sophie Marie Reissiger (Master thesis, 2016)Seaweeds have a long tradition of being a part of the diet in many Asian countries. In Europe seaweeds have mainly been utilized industrially, and especially for their content of phycocolloids, this includes Norway. Due ... -
Exploiting mannuronan C-5 epimerases in commercial alginate production
Tøndervik, Anne; Aarstad, Olav Andreas; Aune, Randi; Maleki, Susan; Rye, Philip D; Dessen, Arne; Skjåk-Bræk, Gudmund; Sletta, Håvard (Peer reviewed; Journal article, 2020)Alginates are one of the major polysaccharide constituents of marine brown algae in commercial manufacturing. However, the content and composition of alginates differ according to the distinct parts of these macroalgae and ... -
Extraction, Characterization, and Biological Activities of Laminarin and Fucoidan from Laminaria hyperborea
Henriksson, Emilia Linnea (Master thesis, 2019)Fucoidan og laminaran finnes som biprodukter i sidestrømmer som stammer fra alginatproduksjon. Utnyttelse av restråstoff fra tare kan generere produkter av kommersiell verdi, og dermed føre til økonomisk vekst for ... -
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 ... -
Graphene oxide in zinc alginate films: Antibacterial activity, cytotoxicity, zinc release, water sorption/diffusion, wettability and opacity
Frigols, Belen; Marti, Miguel; Salesa, Beatriz; Hernandez-Oliver, Carolina; Aarstad, Olav Andreas; Ulset, Ann-Sissel Teialeret; Sætrom, Gerd Inger; Aachmann, Finn Lillelund; Serrano-Aroca, Angel (Peer reviewed; Journal article, 2019)Alginate is considered an exceptional biomaterial due to its hydrophilicity, biocompatibility, biodegradability, nontoxicity and low-cost in comparison with other biopolymers. We have recently demonstrated that the ... -
Mechanical properties of composite hydrogels of alginate and cellulose nanofibrils
Aarstad, Olav Andreas; Heggset, Ellinor Bævre; Pedersen, Ina S.; Bjørnøy, Sindre Hove; Syverud, Kristin; Strand, Berit Løkensgard (Journal article; Peer reviewed, 2017)Alginate and cellulose nanofibrils (CNF) are attractive materials for tissue engineering and regenerative medicine. CNF gels are generally weaker and more brittle than alginate gels, while alginate gels are elastic and ... -
Novel archaeal thermostable cellulases from an oil reservoir metagenome
Lewin, Anna; Zhou, Jinglie; Pham, Vu Thuy Trang; Haugen, Tone; El Zeiny, Mohamed; Aarstad, Olav Andreas; Liebl, Wolfgang; Wentzel, Alexander; Liles, Mark R. (Journal article; Peer reviewed, 2017)Microbial assemblages were sampled from an offshore deep sub-surface petroleum reservoir 2.5 km below the ocean floor off the coast of Norway, providing conditions of high temperature and pressure, to identify new thermostable ... -
Polymer sequencing by molecular machines: a framework for predicting the resolving power of a sliding contact force spectroscopy sequencing method
Dunlop, Alex; Bowman, Kate; Aarstad, Olav Andreas; Skjåk-Bræk, Gudmund; Stokke, Bjørn Torger; Round, Andrew N (Journal article, 2017)We evaluate an AFM-based single molecule force spectroscopy method for mapping sequences in otherwise difficult to sequence heteropolymers, including glycosylated proteins and glycans. The sliding contact force spectroscopy ... -
Preparation of 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH) and guluronic acid-rich alginate using a unique exo-alginate lyase from Thalassotalea crassostreae
Wang, Damao; Aarstad, Olav Andreas; Li, Jing; McKee, Lauren S.; Sætrom, Gerd Inger; Vyas, Anisha; Srivastava, Vaibhav; Aachmann, Finn Lillelund; Bulone, Vincent; Hsieh, Yves S. Y. (Journal article; Peer reviewed, 2018)Marine multicellular algae are considered promising crops for the production of sustainable biofuels and commodity chemicals. However, their commercial exploitation is currently limited by a lack of appropriate and efficient ... -
Production, characterization, and application of an alginate lyase, AMOR_PL7A, from hot vents in the Arctic mid-ocean ridge
Vuoristo, Kiira; Fredriksen, Lasse; Oftebro, Maren; Arntzen, Magnus Øverlie; Aarstad, Olav Andreas; Stokke, Runar; Steen, Ida Helene; Hansen, Line Degn; Schüller, Reidar Barfod; Aachmann, Finn Lillelund; Horn, Svein Jarle; Eijsink, Vincent (Peer reviewed; Journal article, 2019)Enzymatic depolymerization of seaweed polysaccharides is gaining interest for the production of functional oligosaccharides and fermentable sugars. We describe a thermostable alginate lyase belonging to Polysaccharide Lyase ... -
Sequential extraction and fractionation of four polysaccharides from cultivated brown algae Saccharina latissima and Alaria esculenta
Sandberg Birgersson, Paulina Anna Teresia; Oftebro, Maren; Strand, Wenche Iren; Aarstad, Olav Andreas; Sætrom, Gerd Inger; Sletta, Håvard; Arlov, Øystein; Aachmann, Finn Lillelund (Journal article; Peer reviewed, 2023)Norway has a well-established seaweed industry based on extraction of alginates from wild harvested brown algae, Laminaria hyperborea (LH). However, further expansion of wild harvest is limited, and cultivated seaweed can ... -
Structural and functional characterization of the R-modules in alginate C-5 epimerases AlgE4 and AlgE6 from Azotobacter vinelandii
Buchinger, Edith; Knudsen, Daniel H.; Behrens, Manja A.; Pedersen, Jan Skov; Aarstad, Olav Andreas; Tøndervik, Anne; Valla, Svein; Skjåk-Bræk, Gudmund; Wimmer, Reinhard; Aachmann, Finn Lillelund (Journal article; Peer reviewed, 2014)The bacterium Azotobacter vinelandii produces a family of seven secreted and calcium-dependent mannuronan C-5 epimerases (AlgE1–7). These epimerases are responsible for the epimerization of β-d-mannuronic acid (M) to ... -
Structure–Activity Relationships of Low Molecular Weight Alginate Oligosaccharide Therapy against Pseudomonas aeruginosa
Pritchard, Manon F.; Powell, Lydia C.; Adams, Jennifer Y. M.; Menzies, Georgina; Khan, Saira; Tøndervik, Anne; Sletta, Håvard; Aarstad, Olav Andreas; Skjåk-Bræk, Gudmund; McKenna, Stephen; Buurma, Niklaas J.; Farnell, Damian J. J.; Rye, Philip D.; Hill, Katja E.; Thomas, David W. (Peer reviewed; Journal article, 2023)Low molecular weight alginate oligosaccharides have been shown to exhibit anti-microbial activity against a range of multi-drug resistant bacteria, including Pseudomonas aeruginosa. Previous studies suggested that the ... -
Variations in the chemical composition of Norwegian cultivated brown algae Saccharina latissima and Alaria esculenta based on deployment and harvest times
Arlov, Øystein; Nøkling-Eide, Katharina; Aarstad, Olav Andreas; Jacobsen, Synnøve Strand; Langeng, Anne-Mari; Borrero Santiago, Ana Rocio; Sæther, Maren; Rustad, Turid; Aachmann, Finn Lillelund; Sletta, Håvard (Journal article; Peer reviewed, 2024)Brown algae exhibit large seasonal variation in their composition based on nutrient and sunlight access, as well as other environmental factors. The continued growth of brown algae cultivation in Europe is dependent on ...