The methanol:oil molar ratio can have a significant effect on the reaction yield because excess methanol increases the reaction rate and drives high yield of biodiesel, while a high concentration of methanol leads to inactivation of lipases. In this study, experiments were performed at different molar ratios of methanol to WCO ranging from 3:1 (stoichiometric ratio) to 11:1 both in hexane and cyclohexane with methanol added only once.