원문정보
초록
영어
D-Tagatose production from D-galactose by an L-arabinose isomerase muntant from Geobacillus thermodenitrificans was performed with boric acid. The activity for maximum D-tagatose production was pH 9.0 and 60℃ with boric acid, and pH 8.5 and 65℃ without boric acid. The complexation of boric acid with D-tagatose was greater than with D-galactose in TLC. The conversion from D-galactose to D-tagatose was maximal at 40% (mM/mM) boric acid ratio when the ratio of boric acid to D-galactose was increased at 100 g/L, 200 g/L, and 300g/L D-galactose. The enzyme solution containing 40% (mM/mM) boric acid ratio and 300 g/L D-galactose produced 230 g/L tagatose at pH 8.5 and 60℃ for 20 h, corresponding to a conversion yield of 77% (w/w). The equilibrium shift toward D-tagatose at that ratio was due to the greater
complexing capacity of boric acid to D-tagatose than D-galactose. The conversion yield obtained in this study is the highest reported value for D-tagatose production.