Immobilized recombinant Rhizopus oryzae lipase for the production of biodiesel in solvent free system

Different kinds of macroporous and anion resins were applied to immobilize recombinant Rhizopus oryzae lipase in the initial screening test. Anion exchange resin Amberlite IRA-93 was the most proper support to immobilize R. oryzae lipase by covalent binding technology. The transesterification reaction catalyzed by the immobilized lipase was investigated in a solvent free system. It was found that the anion resins used as the immobilized carriers per se contributed to the promotion of acyl migration in the methanolysis reactions and improved biodiesel yield by about 4–8%. The highest biodiesel yield of 90.5% was achieved under the optimum conditions (enzyme dosage 24 U/goil, methanol to oil molar ratio 4.8:1, water content 60% by weight of oil, temperature 37 °C). There was no obvious loss in immobilized lipase activity after being consecutively used for 7 cycles in the transesterification reactions.