Statistical optimisation of methanolysis of jatropha oil using immobilised R. Oryzae cells in n-hexane system

The ability of immobilised whole cells of R. oryzae cells to catalyse the alcoholysis of jatropha oil with methanol in n-hexane system was investigated. Response surface methodology using central composite design was used to study the effects of important parameters: reaction time, reaction temperature, catalyst concentration, molar ratio of alcohol to oil and water content in five levels on percentage yield of biodiesel. The linear effects of reaction time and catalyst concentration and the quadratic effects of catalyst concentration and molar ratio of alcohol to oil were found to be the significant parameters. The optimum conditions for biodiesel production were found to be: reaction time, 77.25 h; reaction temperature, 40.18°C.; catalyst concentration, 3.70 w/v; molar ratio of alcohol to oil, 1:2.88 and water content, 11.20% (w/w of oil). The predicted yield of biodiesel was 79.87% (w/w) and the experimental yield at the optimised condition was 80.5% (w/w). This confirmed the validity of the proposed model.