Investigation of biodiesel production parameters by transesterification of watermelon waste oil using definitive screening design and produced biodiesel characterization

•New advanced method, definitive screening design applied for process optimization to maximize yield of biodiesel.•High 96.763 % of yield biodiesel was achieved from watermelon waste.•The effect of parameters on biodiesel production was investigated.•Properties of biodiesel produced conformed to ASTM D standards.•Oleic acid is the main dominant unsaturated fatty acid of watermelon waste methyl esters. In the present work, biodiesel was produced from watermelon waste oil by the transesterification process. A definitive screening design was used to investigate the effect of transesterification parameters such as catalyst concentration (4−10%), methanol-to-oil ratio (2−10mol/mol)and reaction temperature (46-60°C). The quadratic regression analysis was used to predict the yield of biodiesel. It is found that the optimum catalyst concentration, methanol-to-oil molar ratio and reaction temperature are 5.51%, 5.77:1 and 60°C, respectively, resulting in a 96.763% yield of methyl esters, which is in excellent confirmation with the predicted value. According to the results, all variables had a significant effect on the yield of biodiesel. The physicochemical property of the extracted watermelon waste oil and produced biodiesel using optimum process parameters was analyzed. The results revealed that the extracted oil and produced biodiesel met the requirements of ASTM and EN14214 (European committee for standardization) standard methods. Oleic acid and Linoleic acid were detected to be the dominant unsaturated fatty acids; while palmitic acid was found to be the highest amount of saturated fatty acid. It can be concluded that a definitive screening design for optimization of transesterification reaction parameters is an effective way to boost the yield of biodiesel. In addition, this method significantly reduces the number of experiments, which is important for a limited amount of raw materials. In general, the finding of this work proposes that the watermelon waste oils seem to be a potential and alternative feedstock for the production of biodiesel from waste materials. [Display omitted]