Enzymatic hollow fiber membrane bioreactor for penicilin hydrolysis

Continuous enzymatic reaction has been proven as an efficient technique for several industrial applications. In this study, a type of hollow fiber membrane bioreactor where penicillin acylase entrapped within membrane pores was applied to continuously hydrolyze Penicillin G. The influences of various operating conditions on immobilization and enzymatic reaction processes were assessed. A mathematical model of the reactor behaviour at steady state condition was also developed. The immobilization results show that penicillin acylase was entrapped more than 90% (100,000 u.a m–2). Due to the much smaller size of 6-APA compared to the membrane pore, the solute diffuses freely through the membrane. However, the immobilized enzyme membrane retained around 35% of the solute. In addition, Km of immobilized penicillin acylase (8.04 mM) was slightly higher than that of free penicillin acylase (7.75 mM). The theoretical results indicated that convective transport was the main mechanism of mass transport even in the case where flux was very low. Low flux rate is important to avoid gel formation or enzyme release from membrane pores and to maximize the degree of conversion.

A type of hollow fiber membrane bioreactor (HFMB) where the enzyme was entrapped inside membrane pores was investigated. The immobilization results show that penicillin acylase was entrapped more than 90% (100,000 u.a/m2). Due to the much smaller size of 6-APA compared to the membrane pore, the solute diffuses freely through the membrane. However, the solute was retained around 35% in case where enzyme was immobilized. In addition, Km of immobilized penicillin acylase (8.04 mM) is slightly higher than that of free penicillin acylase (7.75 mM). Finally, the theoretical results obtained by convective-diffusion model and by convective model are very close to each other indicating that convective transport is the main mechanism of mass transport in these experimental conditions. Higher degree of conversion can be achieved by reducing filtration rate. Low flux rate is also important to avoid gel formation of immobilized enzyme on the membrane or enzyme release from the membrane pores.