Abstract
Rice straw is a lignocellulosic biomass that constitutes a renewable organic substance and alternative source of energy; however, its structure confounds the liberation of monosaccharides. Pretreating rice straw using a TiO2/UV system facilitated its hydrolysis with Accellerase 1000™, suggesting that hydroxyl radicals (OH·) from the TiO2/UV system could degrade lignin and carbohydrates. TiO2/UV pretreatment was an essential step for conversion of hemicellulose to xylose; optimal conditions for this conversion were a TiO2 concentration of 0.1% (w/v) and an irradiation time of 2 h with a UV-C lamp at 254 nm. After enzymatic hydrolysis, the sugar yields from rice straw pretreated with these parameters were 59.8 ± 0.7% of the theoretical for glucose (339 ± 13 mg/g rice straw) and 50.3 ± 2.8% for xylose (64 ± 3 mg/g rice straw). The fermentation of enzymatic hydrolysates containing 10.5 g glucose/L and 3.2 g xylose/L with Pichia stipitis produced 3.9 g ethanol/L with a corresponding yield of 0.39 g/g rice straw. The maximum possible ethanol conversion rate is 76.47%. TiO2/UV pretreatment can be performed at room temperature and atmospheric pressure and demonstrates potential in large-scale production of fermentable sugars.
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This work was supported by Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010-0029626).
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Kang, HK., Kim, D. Efficient bioconversion of rice straw to ethanol with TiO2/UV pretreatment. Bioprocess Biosyst Eng 35, 43–48 (2012). https://doi.org/10.1007/s00449-011-0589-9
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DOI: https://doi.org/10.1007/s00449-011-0589-9