KINETIC AND STABILITY CHARACTERIZATION OF CHROMOBACTERIUM-VISCOSUM LIPASE AND ITS COMPARISON WITH PSEUDOMONAS-GLUMAE LIPASE

A kinetic study of Chromobacterium viscosum lipase was undertaken, and compared with Pseudomonas glumae lipase. Optimum operation conditions were pH 9.0 and 50 degrees C for both enzymes. A substrate specificit y study was also developed. Both enzymes showed higher activity on tri glycerides with a long chain of fatty acid; the specific activity was always higher for C. viscosum lipase. Stability of both enzymes in aqu eous medium at 60 degrees C and pH 9.0 was evaluated. C. viscosum lipa se was three times more stable than P, glumae lipase, with a t(1/2) va lue of 0.75 h. In addition, the activity of C. viscosum lipase with su bstrate concentration was studied with a triolein emulsion. A dependen ce of the intrinsic characteristics of the emulsion was observed. Ther efore, stability of C. viscosum lipase B with reaction products was as sayed in a micellar system. Acid products reduced the specific activit y of the enzyme. Glycerol and high buffer concentration were stabilize rs of enzyme deactivation. Finally, substrate specificity of C, viscos um lipase B in a micellar system was developed with tributyrin, tricap rylin, and triolein. Only tributyrin showed an apparent Michaelis-Ment en kinetic with V-max(app) = 958 U/mg and K-m(app) = 75.5 mM. Tricapry lin and triolein showed diffusion limitations at low substrate concent ration and substrate inhibition at high substrate concentration. Diffu sion parameters were calculated for both these substrates. Mass transf er coefficients (k(1)) were 0.314 Angstrom/min and 1.53 Angstrom/min f or tricaprylin and triolein, respectively. Effectiveness factors (eta) were 0.536 and 0.768 for tricaprylin and triolein, respectively.