Optimization of protease and lipase production by <italic>Bacillus pumilus</italic> SG 2 isolated from an industrial effluent

Abstract

This investigation was aimed at isolating a potent bacterial strain which can produce both protease and lipase. Effluents of meat processing industry, dairy industry, food processing industry and oil industry were collected. Among the four positive strains screened, a bacterial strain identified as Bacillus pumilus SG2 isolated from food processing industry effluent was found to be a comparatively potent producer of both protease and lipase (52U/ml and 38U/ml respectively). The process parameters for the optimal production of both enzymes using this strain were studied. The optimum pH for protease production was 8.0 and that of lipase was 9.0. The optimum temperature was 37oC for production of both enzymes. The optimum incubation time was found to be 36 hours for protease and 63 hours for lipase. The best carbon source for enzyme production was glucose and the best nitrogen sources were yeast extract and casein. Addition of additives like SDS, Triton X-100 and Tween-20 influenced enzyme production. Whey was the best crude substrate that could be used for protease production and castor oil, gingelly oil and olive oil were the best substrates for lipase production. This study has indicated the possibility of producing both protease and lipase simultaneously on a common production medium by a single bacterial strain, Bacillus pumilus.