Simultaneous Saccharification and Fermentation of Jatropha curcas (Linn.) Seed Cake for Production of Bioethanol

摘要

The simultaneous saccharification and fermentation (SSF) of pretreated Jatropha curcas seed cake for the production of bioethanol was reported. Trichoderma reesei and Zymomonas mobilis were selected for further fermentation processes. Various parameters like pH, enzyme loading, temperature, substrate concentration and working volume were selected and optimized using D-optimal statistical approach. Enzyme saccharification rate was evaluated prior to SSF studies. The enzyme works for 96.65% conversion of the polymeric carbohydrate into monomeric carbohydrate at pH = 4.5 treated with NaOH at 50 °C within 36 h. The pretreated substrate was then subjected to SSF process using T. reesei and Z. mobilis. Hence, the optimized condition pH = 4, enzyme load of 0.25%, pretreated substrate concentration of 8%, incubation temperature of 31℃ and working volume of 100 mL were found to obtain 78.52% conversion to ethanol in 24 h of incubation time. Z. mobilis gave the maximum conversion of bioethanol within 24 h. This study shows that Z. mobilis has potential for commercial production of ethanol from lingo-cellulose in SSF processes in industry.