When compared with an alkali-catalysed process for the conversion of coconut oil for biodiesel, an enzyme-based process has the
advantage of minimizing saponification problems due to a relatively
high FFA content. However reaction rates are appreciably slower in the
latter process. In the present study this problem has been addressed at
laboratory scale by increasing enzyme loading and the application of
ultrasonics. Specifically, supplementation with ultrasonics at 43 kHz
permitted nearly 20-fold improvement in conversion rate. The study
also demonstrated that the growth yield on by-product glycerol was
about twice that usually found for growth of yeast on glucose. The challenge now exists to translate this new technology to larger scale systems
and to use immobilized enzyme recycling to further enhance rates and
reduce costs