CHARACTERIZATION AND OVER-EXPRESSION OF A CLONED PSEUDOMONAS LIPASE GENE

Abstract

Triacylglycerollipases (E.C.3.1.1.3) are ubiquitous amongst microbes, plants, and animals and catalyse the hydrolysis of ester bonds of triglycerides to form glycerol and fatty acids. On the other hand, lipases catalyse the reverse esterification reaction in low water conditions, forming glycerides from glycerol and free fatty acids. Moreover, some lipases catalyse transesterification through the exchange ofesterified fatty acids with free fatty acids. These reactions can either be selective toward a specific ester bond in triglycerides or completely non-specific. Besides positional specificity, some lipases demonstrate selectivity toward a particular fatty acid substrate. Since lipases have wide versatility, considerable interest in the industrial uses of lipases has recently developed. Industrial applications of lipases include enzymatic fat splitting, accelerated cheese ripening, production of cocoa butter substitutes, and as a detergent additive. Also, the enanatioselectivity of certain lipases offers an attractive opportunity for the preparation of chiral intermediates for pharmaceutical syntheses. Thelipase from Pseudomonassp. ATCC 21808is of particular interest for potential industrial applications becauseofits high temperature optimum for enzymatic activity (65 deg. C), its thermostability (no activity loss after one week at 50 deg C in a phosphate buffer), and activity over a broad pH range (4-9).