title: Production of DagA, a β-agarase, by streptomyces lividans in glucose medium or mixed-sugar medium simulating microalgae hydrolysate.
abstract: DagA, a β-agarase, was produced by cultivating a recombinant Streptomyces lividans in a glucose medium or a mixed-sugar medium simulating microalgae hydrolysate. The optimum composition of the glucose medium was identified as 25 g/l glucose, 10 g/l yeast extract, and 5 g/l MgCl2·6H2O. With this, a DagA activity of 7.26 U/ml could be obtained. When a mixedsugar medium containing 25 g/l of sugars was used, a DagA activity of 4.81 U/ml was obtained with very low substrate utilization efficiency owing to the catabolic repression of glucose against the other sugars. When glucose and galactose were removed from the medium, an unexpectedly high DagA activity of about 8.7 U/ml was obtained, even though a smaller amount of sugars was used. It is recommended for better substrate utilization and process economics that glucose and galactose be eliminated from the medium, by being consumed by some other useful applications, before the production of DagA.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.
authors.forename: Juyi
authors.initials: J
authors.lastname: Park
authors.forename: Soon-Kwang
authors.initials: SK
authors.lastname: Hong
authors.forename: Yong Keun
authors.initials: YK
authors.lastname: Chang
mesh_terms: D050260:Carbohydrate Metabolism; D003470:Culture Media / Q000737:chemistry*; D006026:Glycoside Hydrolases / Q000096:biosynthesis*; D048170:Streptomyces lividans / Q000201:enzymology* / Q000254:growth & development*
chemical_list: D003470:Culture Media; D006026:Glycoside Hydrolases; C019624:agarase