The specificity of Pseudomonas mendocina 3121-1 lipase. Hydrolysis

Abstract

The substrate specificity of a lipolytic enzyme from Pseudomonas mendocina 3121-1 regarding various oils (linseed, maize, olive, sunflower and soy-bean), triacyl glycerols (TAGs) (triacetin, tributyrin, tricaprin, tripalmitin, tristearin and triolein) and Tween type (20, 40, 60, 80 and 85) non-ionic detergents was investigated. Ps. mendocina lipase showed the highest lipolytic activity with regard to long chain TAGs, especially triolein, i.e. a substrate containing unsaturated fatty acid, and to olive and maize oils. The Tweens were used both as surfactants and substrates. Lipase hydrolysed all Tweens, and the efficiency of the hydrolysis was found to depend on their concentration and structure. This indicated that the Tweens examined could not be used for substrate emulsion stabilization, at least at a concentration of 11–44 mM. The enzyme showed the highest activity on Tween 85, i.e. polyoxyethylensorbitan trioleate, whose structure is close to that of triolein. The catalytic activity towards Tweens was found to be lower than towards triacylglycerols (TAGs) at the same concentration. In the presence of both olive oil emulsion and Tween 85 aqueous solution of a relatively low (0.8% (w/w) concentration the detergent seemed to act as a surfactant rather than a a substrate, because the hydrolysis in the system increased to a higher degree than the decomposition of Tween. Tween 85 was found to be the best substrate among all the detergents studied, and a 10% (w/w) concentration was found to be optimal for the hydrolysis by lipolytic enzyme from Pseudomonas mendocina 3121-1. Keywords: Pseudomonas mendocina lipase, hydrolysis, fats, Tweens