13-13: Optimization of alkali pretreatment with lignocellulosic biomass for bioethanol production

Rice straw is the plentiful lignocellulosic biomass for bioethanol production in the world. According to the Korea National Statistical Office, annual rice straw production in Korea was about 6 million tons. If 50% of annual rice straw production is used for cellulosic bioethanol, it will replace more than 5% of the gasoline consumption in Korea. Therefore, it is necessary to develop bioethanol production with cellulosic materials including rice straw.

In this study, temperature and pressure-controlled expansion reaction system and CO₂-mixed physicochemical pretreatment method is presented for the pretreatment of rice straw. Response surface methodology (RSM) was used to optimization of NaOH concentration, reaction time and temperature for the pretreatment of rice straw. The optimum condition for glucose conversion rate from rice straw were determined as follows: NaOH concentration of 4.48%, temperature of 137.0°C with a reaction time of 29.4min. At this optimum condition, the maximum glucose conversion yield was predicted to be 96.4% by model prediction. In conclusion, about 94% of glucose conversion yield was obtained by verification experiment using optimum conditions after 72h of saccharification.