There are two possible reasons that may cause the decrease in chlorophyll content during the transesterification with an increase in the dose of base catalysts that were mixed with methanol at a fixed catalyst to methanol ratio. First, chlorophyll may dissolved in methanol and then moved to the methanol (polar) phase. This will cause a decrease in the chlorophyll content in the biodiesel produced (mainly located in the hexane phase). Second, the base catalyst may easily react with chlorophyll causing its decomposition as mentioned in the literature (Han et al., 2013).