Large increase in Leuconostoc citreum KM20 dextransucrase activity achieved by changing the strain/inducer combination in an E. coli expression system

J Microbiol Biotechnol. 2012 Apr;22(4):510-5. doi: 10.4014/jmb.1111.11032.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Culture Media / metabolism
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism
  • Gene Expression Regulation, Bacterial
  • Gene Expression*
  • Glucosyltransferases / genetics
  • Glucosyltransferases / metabolism*
  • Lactose / metabolism
  • Leuconostoc / enzymology*
  • Temperature

Substances

  • Bacterial Proteins
  • Culture Media
  • Glucosyltransferases
  • dextransucrase
  • Lactose