Optimization of biodiesel production from jatropha oil using immobilized lipase

Abstract

The objective of this study was to produce biodiesel through an enzymatic transesterification process. In this process, jatropha oil was used as the feedstock to react with methanol in the presence of Rhizopus oryzae lipase catalyst. Rhizopus oryzae lipase was immobilized with an innovated method to avoid inhibition and deactivation effects of glycerol and alcohol. The Lipase immobilization, in turn, made the process of separation much easier in comparison with utilizing free lipase. The effect of four important variables (time, temperature, alcohol/oil molar ratio, and oil moisture content) on the yield of biodiesel was studied. The biodiesel production process was modeled and optimized using Artificial Neural Network (ANN), Response Surface Methodology (RSM), and Genetic Algorithm (GA). Maximum yield percentage of 87.07 and 86.62% was predicted by ANN and RSM, respectively. The experimental amount of 87.1% was achieved at optimum parameters: reaction time of 17 h, temperature of 40 °C, 70 % (wt %) water content and the alcohol/oil molar ratio of 5 %. The physico-chemical properties of the jatropha oil and obtained biodiesel were investigated and compared to ASTM D6751 standard. It was observed that the quality of the produced biodiesel is in an acceptable range. The results of the present study show that the immobilization method is reliable and can enhance the performance of the lipase as the catalyst for biodiesel production with moderate conditions.