Enhancing biodiesel production via a synergic effect between immobilized Rhizopus oryzae lipase and Novozym 435

• ROL-catalyzed biodiesel production was enhanced by a synergic effect.
• Non-regioselective lipases were systematically screened.
• Enzymatic reaction time was shortened from 60 h to 21 h.
• Approximately 80% of the biodiesel yield was retained after 20 cycles.

Industrialization of enzyme-catalyzed biodiesel production has been hindered by low conversion efficiency and long reaction time. As a representative example, Rhizopus oryzae lipase (ROL) exhibited a poor performance in biodiesel production. However, higher yields and shorter reaction time could be achieved by screening different lipases that could synergically catalyze the reaction with ROL. The results showed that Novozym 435 combined with ROL displayed the best performance, with a biodiesel yield that was 30% higher than that of ROL alone in 30 h. Hence, the use of a synergic strategy was investigated systematically. Under optimized conditions, the biodiesel yield was as high as 98.3% and the reaction time was successfully shortened from 60 h to 21 h. Moreover, the combined lipases retained a yield of about 80% after 20 cycles in a solvent-free system. In addition to ROL, the performance of other lipases whose regioselectivity were similar to ROL was improved when they were combined with Novozym 435. In conclusion, synergic catalysis is a promising strategy for enhancing biodiesel yield and minimizing reaction time for ROL.