Therefore, the most widely used method is still catalytic transesterification. Among all catalysts, bases are more widely used in industrial production for their faster reacting rate than acid [6] and lowerprice than enzymes. However, homogenous strong alkyls, the catalyst most widely used in industry, have many disadvantages such as separating problems of catalyst and
product, huge amount of water, sensitive to water and acid,which directly limits the rawmaterials of biodiesel.