Screening and characterization of a novel thermostable lipase with detergent-additive potential from the metagenomic library of a mangrove soil.

One clone (Lip906) exhibiting lipase activity was screened from a metagenomic library by using a medium containing tricaprylin. A novel lipase gene from the inserted fragment of Lip906 was obtained by sequencing. The phylogenetic analysis of Lip906 lipase exhibited 34% and 32% homologue to lipases from Streptomyces sp. MspMP-M5 and Rhodopirellula europaea. This gene was expressed in Escherichia coli (E. coli) BL21 (DE3), and the recombinant protein was purified and characterized. The best substrate of the recombinant Lip906 lipase was p-nitrophenyl myristate (C14). The lipase expressed maximum activity at 74°C and pH7.8, and it was found to be stable at pH values and temperatures ranging from 6.0-8.0 and 4-78°C, respectively. Furthermore, the lipase was found to be highly resistant to commercial detergent, DMSO, and EDTA, whereas its activity was stimulated in the presence of methanol and ethanol at low concentrations. The lipase showed enhanced activity in the presence of Hg, whereas the presence of the metal ions Fe, Ca, Co, and Mg inhibited the activity. These beneficial characteristics of Lip906 lipase provide some advantages for its potential application in industry.