Purification and characterization of a mesophilic lipase from Bacillus subtilis FH5 stable at high temperature and pH

Lipases are a class of enzymes which catalyze the hydrolysis of long-chain triglycerides. Microbial li- pases are currently receiving much attention with the rapid development of enzyme technology. Bacillus subtilis FH5, isolated from tannery wastes, produced a thermostable alkalophilic lipase and was purified to homogeneity as judged by SDS-PAGE. The purification steps included acetone fractionation and sequential column chromatography on DEAE-cellulose, Sephadex G-75 and adsorption chromatography on Hydroxylapatite. The results of chromatographies showed that two types of lipases were present hav- ing molecular weights approximately 62 kDa and 24 kDa, respectively. The purified enzyme was found to be 100% stable at pH 10 and about 80% residual activity was present at 60 °C. The enzyme was found to be stable in the presence of Mg 2+ , Mn 2+ and Ca 2+ ions. K m value was calculated as 5.05 mM and V max as 0.416 μ mol/ml/min. Bacillus subtilis FH5 was isolated from tannery waste, therefore, enzyme is envi- ronmentally compatible for application in leather degreasing proces