Repeated production of fatty acid methyl ester with activated bleaching earth in solvent-free system

The enzymatic transesterification of rapeseed oil and methanol with activated bleaching earth (ABE) as a medium was investigated in a solvent-free system. The initial fatty acid methyl ester (FAME) production rate in the solvent-free system was 2.3-fold lower than that in the organic solvent system, but there was not much difference between the overall reaction rates in the solvent and solvent-free systems. When ABE was added to the reaction mixture consisting of rapeseed oil, methanol and lipase, the repeated batch production of FAME was conducted for nine cycles without a significant inactivation of lipase. However, it was only repeated six times in the rapeseed oil-fed batch process, because of the inactivation of lipase. The FAME yield based on used lipase in the repeated batch process was 55.8 g FAME per gram used lipase, which was two-fold higher than that of the oil-fed batch process.