Characterization of an Alkaline Family I.4 Lipase from Bacillus sp W130-35 Isolated from a Tidal Mud Flat with Broad Substrate Specificity

Abstract

A gene encoding lipolytic enzyme, lip7-3, was isolated from Bacillus sp. W130-35 isolated from a tidal mud flat. The gene encoded a protein of 215 amino acids with a signal peptide composed of 34 amino acid residues. Lip7-3 belonged to the family I.4 lipase and showed its maximal activity at pH 9.0 and 60 degrees C. Its activity increased in the presence of 30% methanol and, remarkably, increased as well to 154.6% in the presence of Ca2+. Lip7-3 preferred p-nitrophenyl octanoate (C8) as a substrate and exhibited broad specificity for short-to long-chain fatty acid esters. Additionally, Lip7-3 showed a low degree of enantioselectivity for an S-enantiomer (e.g., (S)-methyl-3-hydroxy-2-methylpropionate). It efficiently hydrolyzed glyceryl tributyrate, but did not hydrolyze glyceryl trioleate, fish oil, or olive oil. Its substrate specificity and activation by the solvent might offer a merit to the biotechnological enzyme applications like transesterification in the production of biodiesel.