Preparation of biodiesel from soybean oil catalyzed by immobilized Pseudomonas cepacia G63

Transesterification reaction was performed in non-aqueous conditions to prepare biodiesel using soybean oil and methanol as raw materials and immobilized lipase as catalyst.Lipase from Pseudomonas cepacia G63 was immobilized by entrapping with sol-gel prepared from tetramethoxysilane and methyltreimethoxysila.Using the immobilized lipase as catalyst,the effects of water content,enzyme dosage,ratio of methanol to oil and reaction temperature on the transesterification reaction were investigated.The results showed that the optimal conditions were as follows:50℃,molar ratio of methanol to oil 4∶1,5% water and 15% lipase.Under the optimal conditions,methyl esters formation of 96.4% for reaction 48 h was obtained.The immobilized lipase proved to be stable and lost a little activity when was subjected to repeated uses.