Overexpression, purification and characterization of organic solvent stable lipase from Bacillus licheniformis RSP-09

The lipase gene (543 bp) from Bacillus licheniformis RSP-09, a thermophilic isolate, was overexpressed in Escherichia coli BL21 (DE3). It encodes a polypeptide of 181 residues and has 96% identity with Bacillus pumilus B26 lipase gene. The recombinant lipase was purified 19-fold to electrophoretic homogeneity by His-tag chromatography. The molecular mass of the purified recombinant B. licheniformis RSP-09 lipase was found to be 24 kDa. The purified recombinant B. licheniformis RSP-09 lipase exhibited optimal activity at pH 10.0 and 40 degrees C. The apparent K(m) and V(max) values for pNPP were found to be 453 +/- 118 microM and 288.5 +/- 33.67 micromol min(-1) mg protein(-1), respectively. The purified recombinant lipase had a wide range of substrate specificity and exhibited tolerance to both detergents and organic solvents. Thus, enzyme has potential to be employed in detergents and biocatalysis in nonaqueous solvents.