Enzymatic treatment of corn cobs for biodiesel production

The effect of dilute H2SO4 and NaOH in corn cob pretreatment was studied. As measure for pretreatment efficiency, enzymatic digestibility of the pretreated biomass was determined. The influence of acid and alkali concentration, temperature and time of pretreatment was studied. After enzymatic hydrolysis of pretreated biomass, the best conditions for alkali and acid pretreatment were selected. The effect of enzyme and substrate loading rate on efficiency of enzymatic hydrolysis of pretreated corn cobs was studied for selected pretreatment conditions. The highest efficiency was achieved at 20% substrate loading and 30 FPU g-1 glucan of enzyme loading. With corn cobs pretreated at 2 % NaOH at 50oC and residence time of 6 hour hydrolysis efficiency of glucan and xylan was 85, 71 % and 73, 53 %, respectively. Enzymatic hydrolysate of corn cobs pretreated on these conditions was used for cultivation of oleaginous fungus Mortierella isabellina, and microbial lipid concentration of 24, 21 g L-1 was achieved. Based on fatty acid composition it is proved that biodiesel produced from microbial lipids from Mortierella isabelina fulfill European biodiesel standard.