Identification and Partial Purification of a Lipase from a Thermophilic Bacterium Obtained from a NW Spain Hot Spring

Bacillus thermoamylovorans, a moderately thermophilic strain that has been recently isolated from a Galician hot spring, produces an enzyme of around 40 kDa that manifests lipolytic activity. In this work, the design of a partial purification protocol for this enzyme has been performed. The stability window of the crude enzyme has been assessed, testing the conditions that can be used in the purification protocol without losing enzymatic activity. The enzyme appears to be stable at pH values higher than 5 and NaCl concentrations up to 4 M. The enzyme selectively precipitates in the presence of relatively low concentrations of ammonium sulphate, which can be used as an advantageous pre-purification technique. It gains activity in the presence of ethylene glycol, isopropanol and sodium cholate, but loses activity in the presence of Triton X-100. Partial purification using Hydrophobic Interaction Chromatography was performed and mass spectrometry analysis indicated that this enzyme presents homology with staphylococcal lipases.