Bioethanol production from rice and corn husks after enzymatic and microbes hydrolysis and yeast fermentation

Purwoko Tj, Sari SLA, Mahadjoeno E, Sunarto. 2017. Bioethanol production from rice and corn husks after enzymatic and microbes hydrolysis and yeast fermentation. Bioteknologi 14: 19-23. Bioethanol is a renewable resource that can be produced from fermented cellulosic biomass. The use of lignocellulosic materials from agricultural wastes provides a low-cost fermentative substrate. Lignocellulosic ethanol production involves acid or enzymatic hydrolysis. The enzymatic hydrolysis is high cost however in environmental issue this step is favorable. The purpose of this research was to compare bioethanol production after microbes and cellulosic enzymes hydrolysis following yeast Saccharomyces cerevisiae fermentation from rice and corn husks.The rice and corn husks (1 kg) were each suspended into water until the volumes reached 5 L. The sample mixtures were treated with 2.5 mg/L cellulases, 5 g/L multienzymes, and 5 mL/L EM4 respectively. The mixtures were stirred for 24 hours at pH 5.7 and 35°C. After hydrolysis, the samples (100 mL) were treated by 1, 2, and 3 % w/v Baker’s yeasts. The samples were fermented at incubator shaking for 6 days at 30°C, 90 rpm, and pH 6.5. Sugar concentrations were determined by dinitrosalicylic acid (DNS) colorimetric method. Bioethanol productions and specific gravity method and then compared to IAOC Ethanol Table. Sugar concentrations and bioethanol production after multienzymes hydrolysis of rice and corn husks were 6.54-6.81 mg/mL and 3.17-3.54 mg/mL, respectively. Sugar concentrations of rice and corn husks after multienzymes hydrolysis treatment was higher than EM4 and cellulases hydrolysis treatments. Therefore bioethanol productions of rice and corn husks after multienzymes hydrolysis and yeasts after 2 days fermentation were higher than the others.