Using local agricultural residues for bioethanol production under full optimized processes

Rice straw (RS) and rice husk (RH) were selected as a local agricultural residues for biopolymers (cellulose, hemicellulose and lignin) extraction using 2% alkaline sodium hydroxide at 90oC for almost 3 hours. The extraction process was optimized by Taguchi experimental design method. Results revealed that cellulose was 54.6 % and 52.75 % in case of RS and RH, respectively. Separate hydrolysis and fermentation (SHF) were done using Aspergilus niger crude enzymes and Saccharomyces cerevisiae, which statistically optimized with two experimental design models (Taguchi and Placket-Burman design). Maximum glucose yield from hydrolysis of the extracted cellulose RS (CRS) and cellulose RH (CRH) was 255 mg/g and 120 mg/g, respectively. Bioethanol yield from the obtained fermentable glucose of CRS and CRH were 231.8 mg/g and 269.4 mg/g, respectively. Extraction, hydrolysis and fermentation processes optimization can be an alternative sustainable development approach to utilize this abundant agricultural waste for new and renewable energy.