title: Psychrotrophic Streptomyces spp. cells immobilisation in alginate microspheres produced by emulsification-internal gelation.
abstract: The objective of the investigations was the optimisation of the parameters for cold-adapted Streptomyces MIUG 4 Alga strain cells immobilisation using emulsification-internal gelation technique in calcium alginate microspheres and testing their ability to produce cold-active β-amylase. By Box-Behnken design and response surface methodology, the effects of independent variables were established, which included sodium alginate concentration (A), sodium alginate:living cell ratio (B) and the Span 80 concentration (C) upon microspheres formation and their functionality. Mean diameter of formed microspheres with immobilised biomass and cold-active β-amylase production were chosen as dependent variables in order to increase the yield of starch hydrolysis. Diameters of microspheres <25.5 μm provided large yield of cold-active β-amylase comparing with microspheres with bigger diameter. A 1.5-fold increase in the substrate hydrolysis yield was achieved using the immobilised biocatalyst compared with the crude enzyme extract, after 96 h of substrate bioconversion.
authors.affiliation: Faculty of Food Science and Engineering, Dunărea de Jos University of Galaţi , Galaţi , Romania and.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Cotârleţ
authors.forename: Stefan
authors.initials: S
authors.lastname: Dima
authors.forename: Gabriela
authors.initials: G
authors.lastname: Bahrim
mesh_terms: D000464:Alginates / Q000737:chemistry*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry*; D055162:Biocatalysis; D018914:Cells, Immobilized; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D013302:Streptomyces / Q000201:enzymology*; D001614:beta-Amylase / Q000096:biosynthesis / Q000737:chemistry*
chemical_list: D000464:Alginates; D001426:Bacterial Proteins; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D001614:beta-Amylase