Evolved beta-galactosidases from Geobacillus stearothermophilus with improved transgalactosylation yield for galacto-oligosaccharide production.

ABSTRACT: A mutagenesis approach was applied to the beta-galactosidase BgaB from Geobacillus stearothermophilus KVE39 in order to improve its enzymatic transglycosylation of lactose into oligosaccharides. A simple screening strategy, which was based on the reduction of the hydrolysis of a potential transglycosylation product (lactosucrose), provided mutant enzymes possessing improved synthetic properties for the autocondensation product from nitrophenyl-galactoside and galacto-oligosaccharides (GOS) from lactose. The effects of the mutations on enzyme activity and kinetics were determined. An change of one arginine to lysine (R109K) increased the oligosaccharide yield compared to that for the wild-type BgaB. Subsequently, saturation mutagenesis at this position demonstrated that valine and tryptopha

SUBMITTER: Placier G 

PROVIDER: S-EPMC2753058 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature