Bioconversion of agricultural wastes to produce ?-amylase from Bacillus velezensis KB 2216: Purification and characterization.

Abstract

Bacillus velezensis KB 2216 was the most capable amylase producing strain among 26 isolates. The strain was assayed for alpha-amylase production under submerged fermentation. Amylase was purified through ammonium sulfate precipitation and Sephadex gel chromatography. KB 2216 was recognized to produce 4 different forms of amylase. One form of alpha-amylase was noted to dimeric, named Amy2. The latter SDS-PAGE and zymogram analysis revealed that purified Amy2 was an approximately 97 kDa dimer of two 55 kDa and 42 kDa subunits. Amy2 was exhibited maximum activity at pH 5.5 and 55 ?C and highest stability at the range of pH 5.0 to pH 5.5 and 0 ?C to 4 ?C. Initially, production media inoculated by new MS6 seed media was showed the highest production (17.066 U/ml) compared to conventional seed media (11.420 U/ml). Production media was optimized using various agricultural wastes. The highest ?-amylase production achieved using 4% moong husk and 2% soybean cake as a major source of carbon and nitrogen respectively and also in the presence of 1.5% fructose and 0.5% NaNO3 as additional nutrients for enhancement of ?-amylase biosynthesis (180.06 U/ml). The optimal physical parameters were assessed to the temperature at 35 ?C, pH 5.0 and 72 h incubation period.