Abstract

OPTIMIZATION STUDIES ON ALPHA AMYLASE PRODUCTION BY BACILLUS LICHENIFORMIS DS3 AND BACILLUS SUBTILIS DS7 USING SUBMERGED FERMENTATION

D. Silpa, P. Brahmaji Rao* and G. Kranthi Kumar

Abstract

Microbial Amylases have several agricultural, clinical, industrial, and pharmaceutical applications. For the production of α-amylases 10 bacterial strains were isolated from banana field soils, Guntur district of Andhra Pradesh, India. From the preliminary studies, among the 10 strains the two strains DS3 and DS7 showed maximum amylase activity on starch hydrolysis test. Further these two strains B. licheniformis DS3 and B. subtilis DS7 were identified upto species level by 16 S rRNA sequencing analysis. These two strains were taken for optimization studies by using submerged fermentation. The effect of different incubation periods, pH, temperatures, metal ions, carbon and nitrogen sources was optimized. The amylase production was best in the conditions of 48 h of incubation, pH 7.0 and at 40⁰ C temperatures. Maximum production (152 U/ml) was recorded in starch nutrient media. Addition of different carbon sources were added to the Starch broth media. Among them highest amylase productions (242.3 U/ml) and (211.4 U/ml) was observed in arabinose and lactose supplemented medium. Different nitrogen sources peptone, beef extract, ammonium sulphate, potassium chloride, Tryptone, LAspargine and yeast extract was assessed and peptone (148.3 U/ml) was found to be the ideal nitrogen source for amylase production. Metal ion CaCl2 influenced the maximum amylase production.

Keywords: Amylase, Bacillus licheniformis, B. subtilis, Di Nitro Salicylic acid (DNS), Starch Agar Medium (SAM).