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BioMed Research International
Volume 2013, Article ID 968692, 9 pages
Research Article

Optimization of the Alkaline Pretreatment of Rice Straw for Enhanced Methane Yield

1College of Forestry, Northwest A&F University, Yangling, Shaanxi Province 712100, China
2Research Center for Recycling Agricultural Engineering Technology of Shaanxi Province, Yangling, Shaanxi Province 712100, China
3College of Agronomy, Northwest A&F University, Yangling, Shaanxi Province 712100, China

Received 14 September 2012; Accepted 16 November 2012

Academic Editor: Shi-You Ding

Copyright © 2013 Zilin Song et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The lime pretreatment process for rice straw was optimized to enhance the biodegradation performance and increase biogas yield. The optimization was implemented using response surface methodology (RSM) and Box-Behnken experimental design. The effects of biodegradation, as well as the interactive effects of Ca(OH)2 concentration, pretreatment time, and inoculum amount on biogas improvement, were investigated. Rice straw compounds, such as lignin, cellulose, and hemicellulose, were significantly degraded with increasing Ca(OH)2 concentration. The optimal conditions for the use of pretreated rice straw in anaerobic digestion were 9.81% Ca(OH)2 (w/w TS), 5.89 d treatment time, and 45.12% inoculum content, which resulted in a methane yield of 225.3 mL/g VS. A determination coefficient () of 96% was obtained, indicating that the model used to predict the anabolic digestion process shows a favorable fit with the experimental parameters.