Production of extracellular alkaline protease from Bacillus subtilis RSKK96 with solid state fermentation

Abstract

The production of extracellular alkaline protease by producing Bacillus subtilis RSKK96 was studied with solid state fermentation (SSF). Different agro residues as substrate were studied for enzyme production. The highest enzyme production was expressed with lentil husk as units per mass of dry substrate (3937.0 U/mg). Production parameters were optimized as incubation time 120 h, extraction medium Triton-X100 1%, initial moisture content 30%, initial pH 9.0. The high level of alkaline protease was obtained in the medium containing arabinose followed by lactose, galactose, and fructose. Among various nitrogen sources, beef extract was found to be the best inducer of alkaline protease, while other nitrogen sources repressed enzyme production. Among metal salts FeSO4.7H2O and MgSO4.7H2O was found to increase protease production. The maximum enzyme production (5759.2 U/mg) was observed with lentil husk in 1000 mL of fermentation medium volume.