In this work, the optimization of transesterification process parameters for the production of Manilkara Zapota Methyl Ester (MZME) has been studied. Molar ratio of methanol to oil, time of reaction, temperature of reaction, and concentration of catalyst were the four parameters considered in the study. Taguchi experimental design was used for the optimization of the above mentioned four process parameters of transesterification. The physicochemical properties and fatty acid methyl ester concentrations were experimentally analyzed. The experimental study revealed that 50 degrees C temperature of reaction, 90 min of time of reaction, 6:1 M ratio of methanol to oil and 1 wt% of concentration of catalyst are the optimal process parameters. Also the study revealed that out of the four parameters considered, methanol to oil molar ratio is most effective in controlling the optimal biodiesel production. The optimal conditions yielded 94.83% of biodiesel. The biodiesel MZME produced with the optimized process parameters meets the global standards for biodiesel EN 14214 and hence could be considered as a suitable substitute for fossil diesel in unmodified diesel engine applications. (C) 2014 Elsevier Ltd. All rights reserved.