Influence of temperature on protein hydrolysis in a cyclic batch enzyme membrane reactor

A cyclic batch enzyme membrane reactor (CBEMR) incorporating a 8000-Da polyethersulphone membrane was intended for enhancing the enzyme (Protex 6L from Bacillus licheniformis, EC. 3.4.21.62) use in the production of a whey protein hydrolysate. A mechanistic mathematical model comprising zero-order kinetics for the hydrolysis and second-order deactivation for the enzyme was proposed and validated through experiments. The influence of reaction temperature was studied and process optimisation (given the production requirements) was performed in terms of number of batch reactions that minimise the total amount of enzyme used. The optimal operation of the CBEMR allowed savings of up to 44 and 32% of enzyme compared to the single batch operation mode at 50 and 60 °C, respectively. No enzyme savings were detected when temperature was fixed at 70 °C. In general, the optimal operation temperature was 60 °C, yielding lower enzyme consumption for all productivities of the reactor.