Molecular Cloning and Expression in Escherichia coli of Pseudomonas aeruginosa lipase gene

In this study genomic library was constructed from P. aeruginosa purified DNA and screened for these two lipases genes in an attempt to isolate both of these genes and subclone them on the same plasmid. Primary screening of a genomic library constructed on pTrcHis (A, B, C) plasmid showed a number of potential lipase positives clones when expressed in E. coli DH5α. Surprisingly, most of these potential positives showed a specific DNA insert with a molecular size of 1.2 kbp when cut with restriction enzyme. Pilot protein expression study showed a specific protein band of a molecular weigh of 15.0 kDa when expressed in E. coli DH5α that induced with IPTG this matched the corresponding molecular weight of the native enzyme that isolated from the parent strain. Moreover, a serine protease inhibitor, PMSF showed an inhibitory effect on the activity of the recombinant enzyme while EDTA showed slight inhibitory effect.