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Strain improvement by mutation for enhanced production of starch‐saccharifying glucoamylase from Bacillus licheniformis
Author(s) -
Ghani Maria,
Aman Afsheen,
Rehman Haneef U.,
Siddiqui Nadir N.,
Qader Shah A. U.
Publication year - 2013
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.201200278
Subject(s) - bacillus licheniformis , fermentation , starch , mutant , food science , strain (injury) , hydrolysis , enzyme , biochemistry , chemistry , enzyme assay , biology , bacteria , bacillus subtilis , gene , genetics , anatomy
A natural isolate, Bacillus licheniformis 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 B. licheniformis 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.