Lamare S, Lortie R, Legoy M D
Laboratoire du Génie Protéique et Cellulaire, Université de La Rochelle, Avenue Marillac, 17042 La Rochelle Cedex 1, France.
Biotechnol Bioeng. 1997 Oct 5;56(1):1-8. doi: 10.1002/(SICI)1097-0290(19971005)56:1<1::AID-BIT1>3.0.CO;2-O.
Fusarium solani cutinase supported onto Chromosorb P was used to catalyze transesterification (alcoholysis) and hydrolysis on short volatile alcohols and esters in a continuous gas/solid bioreactor. In this system, a solid phase composed of a packed enzymatic preparation was continuously 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 rates. The effect of the hydration state of the biocatalyst on the kinetics was studied for 3 conditions of hydration (a(w) = 0.2, a(w) = 0.4 and 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. solani cutinase was found to have an unusual kinetic behavior. A sigmoid relationship between the rate of transesterification and the activity of methyl propionate was observed, suggesting some form of cooperative activation of the enzyme by one of its substrate. For the hydrolysis of short volatile propionic acid alkyl esters, threshold effects on the reaction rate, highly depending on the water activity and the substrate polarity, are reported.
负载于Chromosorb P上的茄病镰刀菌角质酶用于在连续气/固生物反应器中催化短链挥发性醇和酯的酯交换反应（醇解）和水解反应。在该系统中，由填充的酶制剂组成的固相被载气连续渗透，载气同时输送底物并去除反应产物。为了获得初始反应速率，在不同操作条件下进行了动力学研究。研究了生物催化剂的水合状态对动力学的影响，考察了3种水合条件（a(w)=0.2、a(w)=0.4和a(w)=0.6）下丙酸甲酯与正丙醇的醇解反应，以及5种水合水平（从a(w)=0.2到a(w)=0.6）下丙酸甲酯、乙酯或丙酯的水解反应。发现茄病镰刀菌角质酶具有异常的动力学行为。观察到酯交换反应速率与丙酸甲酯活性之间呈S形关系，表明其一种底物对该酶有某种形式的协同激活作用。对于短链挥发性丙酸烷基酯的水解反应，报道了对反应速率的阈值效应，该效应高度依赖于水分活度和底物极性。
