초록
<P><B>Abstract</B></P><P>A natural isolate, <I>Bacillus licheniformis</I> KIBGE‐IB3, was subjected to mutational analysis for the enhanced production of glucoamylase. Randomly generated mutants were initially screened for enzyme production and after secondary screening <I>B. licheniformis</I> KIBGE‐IB3M67 demonstrated maximum glucoamylase production with improved starch saccharifying capability. Enzyme activity from KIBGE‐IB3M67 reached up to 25 kU/mg by strain improvement, which was nearly twofold increase in enzyme production as compared to the parent strain. SEM revealed that raw potato starch is more profoundly hydrolyzed when treated with mutant glucoamylase. Successful mutation also reduced the fermentation time from 48 to 24 h for glucoamylase production, optimum fermentation pH and temperature slightly shifted from 7.0 (wild) to 7.5 (mutant), from 30 to 50°C (wild), and from 20 to 55°C (mutant), respectively. Reduction in fermentation time and enhanced starch saccharification ability makes this mutant (KIBGE‐IB3M67) an attractive candidate for the production of glucoamylase at commercial level.</P>