Author(s): Kim I, Lee B, Park JY, Choi SA, Han JI
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Abstract In this study, nitric acid (HNO₃) was evaluated as an acid catalyst for rice straw pretreatment, and, after neutralization, as a sole nitrogen source for subsequent fermentation. Response surface methodology was used to obtain optimal pretreatment condition with respect to HNO₃ concentration (0.2-1.0\%), temperature (120-160 °C) and reaction time (1-20 min). In a condition of 0.65\% HNO₃, 158.8 °C and 5.86 min, a maximum xylose yield of 86.5\% and an enzymatic digestibility of 83.0\% were achieved. The sugar solution that contained nitrate derived from the acid catalyst supported the enhancement of ethanol yield by Pichia stipitis from 10.92 g/L to 14.50 g/L. The results clearly reveal that nitric acid could be used not only as a pretreatment catalyst, but also as a nitrogen source in the fermentation process for bioethanol production. It is anticipated that the HNO₃-based pretreatment can reduce financial burden on the cellulosic bioethanol industry by simplifying after-pretreatment-steps as well as providing a nitrogen source. Copyright © 2013 Elsevier Ltd. All rights reserved.
This article was published in Carbohydr Polym
and referenced in Journal of Environmental Analytical Chemistry