Structural Analysis of Alkaline Pretreated Rice Straw for Ethanol Production

Paripok Phitsuwan, Chutidet Permsriburasuk, Sirilak Baramee, Thitiporn Teeravivattanakit, Khanok Ratanakhanokchai
2017 International Journal of Polymer Science  
Rice straw (RS) is an abundant, readily available agricultural waste, which shows promise as a potential feedstock for Asian ethanol production. To enhance release of glucose by enzymatic hydrolysis, RS was pretreated with aqueous ammonia (27% w/w) at two pretreatment temperatures: room temperature and 60°C. Statistical analysis indicated similarity of enzymatic glucose production at both pretreatment temperatures after 3-day incubation. Chemical composition, FTIR, and EDX analyses confirmed
more » ... alyses confirmed the retention of glucan and xylan in the pretreated solid, but significant reduction of lignin (60.7% removal) and silica. SEM analysis showed the disorganized surfaces and porosity of the pretreated RS fibers, thus improving cellulose accessibility for cellulase. The crystallinity index increased from 40.5 to 52.3%, indicating the higher exposure of cellulose. With 10% (w/v) solid loadings of pretreated RS, simultaneous saccharification and fermentation yielded a final ethanol concentration of 24.6 g/L, corresponding to 98% of maximum theoretical yield. Taken together, aqueous ammonia pretreatment is an effective method to generate highly digestible pretreated RS for bioethanol production and demonstrates potential application in biorefinery industry.
doi:10.1155/2017/4876969 fatcat:qmkbone5pfdkfh72tdcou6adga