KINETIC-STUDIES OF FUSARIUM-SOLANI PISI CUTINASE USED IN A GAS SOLID SYSTEM - TRANSESTERIFICATION AND HYDROLYSIS REACTIONS/

Fusarium solani cutinase supported onto Chromosorb P was used to catal yze transesterification (alcoholysis) and hydrolysis on short volatile alcohols and esters in a continuous gas/solid bioreactor. In this sys tem, a solid phase composed of a packed enzymatic preparation was cont inuously percolated with carrier gas which fed substrates and removed reaction products simultaneously. A kinetic study was performed under differential operating conditions in order to get initial reaction rat es. The effect of the hydration state of the biocatalyst on the kineti cs was studied for 3 conditions of hydration (a(w) = 0.2, a(w) = 0.4 a nd a(w) = 0.6), the alcoholysis of propionic acid methyl ester with n- propanol, and for 5 hydration levels (from a(w) = 0.2 to a(w) 0.6) for the hydrolysis of propionic acid methyl, ethyl or propyl esters. F. s olani cutinase was found to have an unusual kinetic behavior. A sigmoi d relationship between the rate of transesterification and the activit y of methyl propionate was observed, suggesting some form of cooperati ve activation of the enzyme by one of its substrate. For the hydrolysi s of short volatile propionic acid alkyl esters, threshold effects on the reaction rate, highly depending on the water activity and the subs trate polarity, are reported. (C) 1997 John Wiley & Sons, Inc.