Optimization of Diluted Organic Acid Pretreatment on Rice Straw Using Response Surface Methodology
Lignocellolusic material is a substance that is resistant to be degraded by microorganisms or hydrolysis enzymes. To be used as materials for biofuel production, it needs pretreatment process to improve efficiency of hydrolysis. In this work, chemical pretreatments on rice straw using three diluted organic acids, including acetic acid, citric acid, oxalic acid, were optimized. Using Response Surface Methodology (RSM), the effect of three pretreatment parameters, acid concentration, treatment time, and reaction temperature, on pretreatment efficiency were statistically evaluated. The results indicated that dilute oxalic acid pretreatment led to the highest enhancement of enzymatic saccharification by commercial cellulase and yielded sugar up to 10.67 mg/ml when using 5.04% oxalic acid at 137.11 oC for 30.01 min. Compared to other acid pretreatment by acetic acid, citric acid, and hydrochloric acid, the maximum sugar yields are 7.07, 6.30, and 8.53 mg/ml, respectively. Here, it was demonstrated that organic acids can be used for pretreatment of lignocellulosic materials to enhance of hydrolysis process, which could be integrated to other applications for various biorefinery processes.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1100825Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF
 R. Sathre, “Comparing the heat of combustion of fossil fuels to the heat accumulated by their lifecycle greenhouse gases,” in 2014 Fuel., vol. 115, pp. 674-677.
 V. Menon, M. Rao, “Trends in bioconversion of lignocellulose: Biofuels, platform chemicals & biorefinery concept,” in 2012 Prog Energy Combust Sci., vol. 38, pp. 522-550.
 R. E. Hage, L. Chrusciel, L. Desharnais, N. Brosse, “Effect of autohydrolysis of Miscanthus × giganteus on lignin structure and organosolv delignification,” in 2010 Bioresour. Technol., vol. 101, pp. 9321–9329.
 G. Y. S. Mtui, “Recent advances in pretreatment of lignocellulosic wastes and production of value added products” in 2009 Afr J of biotechnol., vol. 8 , pp. 1398-1415.
 Y. Zheng1, J. Zhao, F. Xu, Y. Li, “Pretreatment of lignocellulosic biomass for enhanced biogas production,” in 2014 Prog Energy Combust Sci., vol. 42, pp. 35–53.
 I. Kim, B. Lee, J. Park, S. Choi, J. Han, “Effect of nitric acid on pretreatment and fermentation for enhancing ethanol production of rice straw” in 2014 Carbohyd. Polym., vol. 99, pp. 563-567.
 N. Gil, S. Ferreira, M. E. Amaral, F. C. Domingues, A. P. Duarte, “The influence of dilute acid pretreatment conditions on the enzymatic saccharification of Erica spp. for bioethanol production” in 2010 Ind. Crop Prod., vol. 32 pp. 29-35.
 F. Monlau, A. Barakat1 , J.P. Steyer, H. Carrere, “Comparison of seven types of thermo-chemical pretreatments on the structural features and anaerobic digestion of sunflower stalks” in 2012 Bioresour. Technol., vol. 120 pp. 241–247.
 A.T.W.M. Hendriks, 1, G. Zeeman, “Pretreatments to enhance the digestibility of lignocellulosic biomass,” in 2010 Bioresour. Technol., vol. 100 pp. 10–18.
 A. M. J. Kootstra, H. H. Beeftink, E. L. Scott, J. P.M. Sanders, "Comparison of dilute mineral and organic acid pretreatment for enzymatic hydrolysis of wheat straw." in 2009 Biochem. Eng. J., vol. 46 pp. 126-131.
 X. Zhao, L. Wangb, X. Lu, S. Zhang, "Pretreatment of corn stover with diluted acetic acid for enhancement of acidogenic fermentation." in 2014 Bioresour Technol., vol. 158, pp. 12-18.
 V. Soest, P. J., J. B. Robertson, B. A. Lewis, “Methods of dietary fibre, neutral detergent fibre, and non strach polysaccharides in relation to animal nutrition”. in 1991 J. Dairy Sci., vol. 74, pp.3583-3597.
 AOAC International, "Total dietary fiber in foods, enzymaticgravimetric method". in "Official methods of analysis of AOAC international". in 2003, 17th ed. 985.29. Gaithersburg, MD, U.S.A.
 G. L. Miller, “Use of dinitro salicylic acid reagent for determination of reducing sugar,” in 1959 Anal. Chem., vol. 31, no. 3, pp. 426–428.