Therefore, there exists limiting enzyme concentration beyond which there is no effect on the methyl ester yield. The results obtained are in agreement with the previous studies [14] and [15] where higher enzyme concentration had no effect on FAME yield or slight decrease in the yield was observed. They suggested that enzyme at higher concentrations tend to agglomerates and tend to decrease the actual effective reaction area on the oil–water interface and thus the reaction rate decreases with the increase of lipase concentration [15].