The N-terminal His-tag and the recombination process affect the biochemical properties of Staphylococcus aureus lipase produced in Escherichia coli

The part of the gene encoding the mature Staphylococcus aureus lipase (SAL3) was cloned using PCR technique. The sequence corresponding to the mature lipase was subcloned into pET-14b or pOP-T expression vector and expressed in E. coli BL21 (DE3). The tagged (His6-SAL3) and untagged (r-SAL3) Staphylococcus aureus lipases were purified to homogeneity using Ni-NTA resin and classical chromatographic techniques, respectively. We performed a comparative study on the biochemical properties of two recombinant Staphylococcus aureus lipases and the wild type form. The major differences among these lipases are mainly reflected in their stability at high and low temperature, measured in aqueous media as well as in various organic solvents. Furthermore, our results indicate that the presence of the His-tag in the N-terminus of the SAL3 as well as the recombination process significantly affect the adsorption of these proteins onto CaCO3 used as support and their capacity to synthesise diesel additive by esterification of butanol with oleic acid.