Cloning And Expressing Of Lipases For Preparation Of L-menthol

Two lipase gene from P. alcaligenes XI and S.maltophilia X2were cloned and expressed in Escherichia coli.Two genomic libraries were constructed by pUC19and E.coil system, and the gene pal and sml coding for the lipase (PAL) and lipase (SML) were isolated, respectively, the two protein have the same conserved domain GISYG, and their catalytic triad amino acid were Ser-Asp-His.The genes were cloned into the plasmid pET30a(+), and then transformed into the E.coil BL21(DE3). PAL and SML had almost the same molecular weight of about51kDa. The production of the hydro lase were89000U/Land90600U/L, respectively The two enzymes were further purified, and studied on the enzymatic characteristics including the optimal temperature and pH, the sbtrate specificity and the effects of the metal ions no the their activities. We studied on the activity of two enzyme on catalyzing asymmetric hydrolysis and transesterificaiton of racemic menthl substrate. This study provides the fundamental work for the resolution of4Pairs of Enantiomers of Menthol.