[Immobilized lipase-catalyzed synthesis of biodiesel from crude cottonseed oil]

We investigated the transesterification of crude cottonseed oil with methyl acetate to biodiesel, by using Lipozyme TL IM and Novozym 435 as catalysts. Results showed that the biodiesel yield significantly increased with the addition of methanol into the reaction system, and the highest biodiesel yield of 91.83% was achieved with the optimum conditions as follows: n-hexane as solvent, molar ratio of methyl acetate to oil 9:1, 3% methanol based on the oil mass to inhibit the creation of acetic acid, 10% Lipozyme TL IM and 5% Novozym 435 as catalyst based on the oil mass, reaction temperature 55 degrees C and reaction time 8 h. Additionally, we explored the kinetics of lipase-catalyzed crude cottonseed oil to biodiesel, and proposed a kinetic model.