Monday, May 4, 2009
9-72
Optimization of biodiesel production by fungus cells immobilized in fibrous supports
Jyh-Ping Chen and Gen-Hsu Lin. Department of Chemical and Materials Engineering, Chang Gung University, 259 Wen Hwa 1st Rd., Kwei-San, Taoyuan, Taiwan
A circulating packed-bed bioreactor system using fibrous nonwoven fabric as the immobilization matrix was suitable for simultaneous cell growth and immobilization of Rhizopus oryzae fungus cells. The optimal culture time considering both cell weight and transesterification activity was 72 hr. The immobilized whole cell biocatalyst was suitable for biodiesel production by methanolysis of oil after drying and suitable post-treatment. The best treatment method for immobilized whole cell biocatalyst for biodiesel production was by permeabilizing the cells in acetone for 90 min and incubating the permeabilized cells in soybean oil for 72 hr. Response surface methodology and 5-level-5-factor central composite rotatable design was proved to be a powerful tool for the optimization of methanolysis conditions catalyzed by immobilized R. oryzae whole cell biocatalyst. A second-order model could be obtained to describe the relationship between the methyl ester yield and the significant parameters (water content, substrate molar ratio, cell concentration, and reaction time). Under the optimal condition, 10.97% water content (based on oil), 0.64 molar ratio of methanol to oil, 2.25%(w/w) cell weight (based on oil), and 23.3 hr reaction time, the predicted values of methyl ester yield was about 72.6%. Validation experiments with predicted yield of 70.77 ± 2.46% verified the availability and the accuracy of the model. The predicted value was in agreement with the experimental value.