Expression and Biochemical Characterization of a Thermophilic Organic Solvent-Tolerant Lipase from Bacillus sp. DR90

Abstract

The objective of the present study was the isolation, molecular cloning and biochemical characterization of a thermophilic organic solvent-resistant lipase from Bacillus sp. DR90. The lipase gene was expressed in Escherichia coli BL21(DE3) using pET-28a(+) vector. The purification of recombinant lipase was conducted by nickel affinity chromatography and its biochemical properties were determined. The lipase sequence with an ORF of 639 bp contains the conserved pentapeptide Ala-His-Ser-Met-Gly. His-tagged recombinant lipase had a specific activity of 1,126 U/mg with a molecular mass of 26.8 kDa. The cloned lipase was optimally active at pH 8.0 and 75 °C representing high stability in broad ranges of temperature and pH. High performance liquid chromatography was used to determine the major compounds released during the lipase-catalyzed reaction of p-nitrophenyl derivatives as well as the substrate specificity. The purified lipase showed high compatibility towards various organic solvents, surfactants and commercial solid/liquid detergents; therefore the recombinant DR90 lipase could be considered as a probable candidate for future applications, predominantly in detergent processing industries.

Lipase catalysis in organic solvents: advantages and applications

“…The enzymes, which can work optimally in harsh conditions such as wide pH range, high temperature, varying salt conditions and in the presence of toxic organic solvents without losing the activities are needed to be explored. The thermophilic enzymes in comparison to mesophilic enzymes display higher resistance to unfavorable conditions and withstand in extreme environments [ 30 ]. A particular interest relies on the capacity of a lipase to catalyze such reactions and consequently making possible the synthesis of fine compounds used for manufacturing products of high cumulative value, e.g.…”