Identification and over-expression of a thermostable lipase from Geobacillus thermoleovorans Toshki in Escherichia coli

SummaryA newly isolated thermophilic strain producing thermostable lipase was identified based on 16S rRNA sequencing, where phylogenetic analysis revealed its closeness to Geobacillus thermoleovorans. Thermostable lipase from this bacterium was cloned using consensus degenerate PCR primers. For over-expression in Escherichia coli, the lipase gene was sub-cloned in pET 15b vector with a strong T7 promotor. Lipase activity was approximately 4.5-fold higher than in the wild-type strain. The lipase enzyme was thermostable at 60 °C and pH 8, whereas a 30% residual activity was retained when incubated for 1 h at 100 °C. Optimum lipase expression was obtained in 2×YT medium after 70 min of induction by IPTG.