Optimizations of process parameters for biodiesel production have been studied in detail by many researchers. This is mainly because these process parameters have shown important contribution towards attaining maximum biodiesel conversion. The biodiesel process parameters studied here include oil-to-ethanol molar ratio, water content, enzyme loading, reaction temperature, mixing intensity, and finally reaction time. Enzymatic transesterification of crude Jatropha oil was carried out in a 50-ml baffled conical flask (Corning, USA) in an orbital shaker incubator (Heidolp, Germany). This setup was used as a stirred tank batch reactor for the rest of the experiments. The following standard set of reaction conditions were used as the baseline in the optimization studies. The initial conditions were 10 g Jatropha oil, 2 g ethanol (ethanol-to-oil ratio 1:4), 1 g water, 100 mg free lipase or 5.2 g immobi­lized lipase, 35°C, 200 rpm (rotations per minute), and 24-h reaction time. For example, when the effect of oil-to-ethanol ratio was assessed, the remaining reac­tion conditions were unchanged: that is, 10 g oil, 1 g water, 5.2 g immobilized lipase, 35°C, 200 rpm (rotations per minute), and 24-h reaction time.