A cold adapt and ethanol tolerant endoglucanase from a marine Bacillus subtilis

摘要

The catalytic properties and thermodynamic kinetics of the endoglucanase from a marine Bacillus subtilis were analyzed. Optimum pH and temperature of the endoglucanase activity were 5.0 and 35 ℃. The endoglucanase activity, melt point temperature was 1.13 folds(247.02 U·ml-1), 2.1 ℃ higher(39.2 ℃)in 6％ ethanol solution than that(218.60 U·ml-1),(37.1 ℃)in free ethanol. At 40 ℃–55 ℃, Gibbs free energy, ΔG, and the content ofα-helix was higher in 6％ ethanol solution than that in ethanol free solution. The increasing of α-helix content led to higher activity and better thermostability in ethanol solution. The cold adapt ethanol tolerant endoglucanase was valuable for bioethanol product by simultaneous saccharification and fermentation process.