Optimization of cultural conditions for production of chitinase by Bacillus laterosporous MML2270 isolated from rice rhizosphere soil

Abstract

A total of 39 chitinolytic bacteria were isolated from 77 rhizosphere soil samples collected from different crop fields in Tamil Nadu state, India. Among them, a strain designated as MML2270, which produced highest chitinolytic activity in primary and secondary screening in colloidal chitin agar was selected and later identified as Bacillus laterosporous. The production of chitinase by B. laterosporous was optimized using different growth media, substrate concentrations, pH, temperature and incubation
period. The maximum chitinase production was observed in yeast nitrogen based medium (YNB) amended with 0.3% colloidal chitin at pH 8.0 and 35°C after four days of inoculation. Under this optimized growth condition, B. laterosporous MML2270 produced a total chitinase activity of 59.05
units/ml as against only 19.7 units/ml in the initial YNB medium stage, which is a three-fold increase.