Wu D R, Cramer S M, Belfort G
Howard P Isermann Department of Chemical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
Biotechnol Bioeng. 1993 Apr 25;41(10):979-90. doi: 10.1002/bit.260411009.
A laboratory-scale multiphase hollow fiber membrane reactor was employed to investigate the lipase-catalyzed enzymatic resolution of racemic glycidyl butyrate. A mathematical formulation was developed to simulate the performance of this system. Model parameters were determined independently (except the effective rate constant, k(s)) and incorporated in the model simulations. In this study, two modes of operation are considered: subtractive resolution, in which the unreacted substrate is recovered in the organic stream; and product recovery, where the optically pure product of the enzymatic reaction is recovered in the aqueous stream. Good agreement was obtained between theoretical predictions and experimental results under a variety of conditions. The effect of mass transport limitations on the performance of this system was investigated. An increase in enzyme loading resulted in a higher Thiele modulus due to an elevated rate constant as well as a concomitant decrease in the effective diffusivity. Optical purity decreased in both subtractive resolution and product recovery at higher Thiele modulus with the effect being more pronounced in the product recovery mode. Finally, normalized plots were established to describe the effect of enzyme immobilization on both the effective enzymes activity and effective diffusivity.
采用实验室规模的多相中空纤维膜反应器研究脂肪酶催化外消旋丁酸缩水甘油酯的酶促拆分。开发了一个数学公式来模拟该系统的性能。模型参数是独立确定的（有效速率常数k(s)除外），并纳入模型模拟中。在本研究中，考虑了两种操作模式：减法拆分，其中未反应的底物在有机物流中回收；以及产物回收，其中酶促反应的光学纯产物在水流中回收。在各种条件下，理论预测与实验结果之间取得了良好的一致性。研究了传质限制对该系统性能的影响。由于速率常数升高以及有效扩散率随之降低，酶负载量的增加导致了更高的西勒模数。在较高的西勒模数下，减法拆分和产物回收中的光学纯度均降低，在产物回收模式下这种影响更为明显。最后，建立了归一化图来描述酶固定化对有效酶活性和有效扩散率的影响。
