Expression, purification and characterization of a functional, recombinant, cold-active lipase (LipA) from psychrotrophic Yersinia enterocolitica

A novel cold-active lipase gene encoding 294 amino acid residues was obtained from the Yersinia enterocolitica strain KM1. Sequence alignment and phylogenetic analysis revealed that this novel lipase is a new member of the bacterial lipase family I.1. The lipase shares the conserved GXSXG motif and catalytic triad Ser85-Asp239-His261. The recombinant protein LipA was solubly and heterogeneously expressed in Escherichia coli, purified by Ni-affinity chromatography, and then characterized. LipA was active over a broad range spanning 15-60 °C with an optimum activity at 25 °C and across a wide pH range from 5.0 to 11.0 with an optimum activity at pH 7.5. The molecular weight was estimated to be 34.2 KDa. The lipase could be activated by Mg2+ and a low concentration (10%) of ethanol, dimethyl sulfoxide, methanol and acetonitrile, whereas it was strongly inhibited by Zn2+, Cu2+ and Mn2+. This cold-active lipase may be a good candidate for detergents and biocatalysts at low temperature.