Kinetics,improved activity and thermostability of endoglucanase and β-glucosidase from a mutant-derivative of aspergillus niger MS82

A mutant ms301 of aspergillus niger ms82 showed 1.5 to 2.5-fold improved endoglucanase and β-glucosidase activity when grown on crude lignocellulosic substrates under solid-state and submerged conditions. indicators of thermal stability of enzymes (tm and t1/2) showed that the wild type and mutant endoglucanase was more heat-resistant compared to β-glucosidase. however,mutant and parent enzymes shared almost the same values for melting temperatures and half-lives. endoglucanase and β-glucosidase from both the strains showed optimum activity under acidic ph. energy of activation (ea) of mutant β-glucosidase was substantially lower than the parent enzyme while ea of mutant endoglucanase was slightly less than the parent. the lowered ea values can be attributed to the improved β-glucosidase activity of the mutant strain. moreover,the ms301 enzymes were better in hydrolyzing purified and crude cellulosic materials than the parent ms82.