Fed-Batch Feeding Strategies for Enzymatic Biodiesel Production

In this work a kinetic model for the enzymatic transesterification of rapeseed oil using a solubilised lipase (Callera Trans L-Thermomyces lanuginos us) was developed from first principles. The model is based on a Ping-Pong Bi-Bi mechanism, with methanol inhibition, along with consideration of the differences in the interfacial and bulk concentrations of the enzyme. The model is then used to evaluate various feeding strategies to improve the enzymatic biodiesel production. The feeding strategies investigated, gave insight into how the methanol should be fed to potentially mitigate enzyme deactivation while improving the biodiesel yield. The best experimental results gave a yield of 703 .76 g FAME L-1 and a reactor productivity of 28.12 g FAME L-1 h-1. In comparison, to reach the same yield, the optimised two step feeding strategy took 6.25 hours less, which equates to an increase the reactor productivity of 36.9 % .