Enzymatic reactions inside a microreactor with a mesoporous silica catalyst support layer Original Research Article

A microreactor containing mesoporous silica thin film that we recently developed [Appl. Catal. A: Gen. 342 (2008) 107–112] was employed to realize a continuous enzymatic reaction. The mesoporous silica thin film served as a catalyst support layer for immobilizing lipase without complex chemical modification. The immobilized lipase showed good enzymatic activity and stability during a 24 h continuous ester hydrolysis reaction. The relation between the product and reactant concentrations indicated that the hydrolysis reaction with immobilized lipase follows Michaelis–Menten kinetics. The activity of the immobilized lipase was evaluated using a mathematical model and was compared with that of unimmobilized lipase in a batch experiment. The obtained turnover number of the immobilized lipase was almost the same as that of the free lipase in the batch experiment, while the Michaelis constant of the immobilized lipase was greater than that in the batch experiment by a factor of 3. A mathematical model was also employed to interpret the results of microreactor experiments performed under various conditions.