title: Large increase in Leuconostoc citreum KM20 dextransucrase activity achieved by changing the strain/inducer combination in an E. coli expression system.
abstract: A recombinant putative dextransucrase (DexT) was produced from Leuconostoc citreum KM20 as a 160 kDa protein, but its productivity was very low (264 U/l). For optimization, we examined enzyme activity in 7 Escherichia coli strains with inducer molecules such as lactose or IPTG. E. coli BL21-CodonPlus(DE3)-RIL exhibited the highest enzyme activity with lactose. Finally, DexT activity was remarkably increased by 12-fold under the optimized culture conditions of a cell density to start induction (OD₆₀₀) of 0.95, a lactose concentration of 7.5 mM, and an induction temperature of 17 degrees C. These results may effectively apply to the heterologous expression of other large DexT genes.
authors.affiliation: Infection Control Material Research Center, Korea Research Institute of Bioscience and Biotechnology-KRIBB, Jeongeup 580-185, Korea.
authors.forename: Jin-A
authors.initials: JA
authors.lastname: Ko
authors.forename: Hyung Jae
authors.initials: HJ
authors.lastname: Jeong
authors.forename: Young Bae
authors.initials: YB
authors.lastname: Ryu
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Young-Jung
authors.initials: YJ
authors.lastname: Wee
authors.forename: Doman
authors.initials: D
authors.lastname: Kim
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kim
authors.forename: Woo Song
authors.initials: WS
authors.lastname: Lee
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D007785:Lactose / Q000378:metabolism; D007934:Leuconostoc / Q000201:enzymology*; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D005964:Glucosyltransferases; C020025:dextransucrase; D007785:Lactose