Alkali Pretreatment and Enzyme Hydrolysis to Enhance the Digestibility of Rice Straw Cellulose for Microbial Oil Production

Main Article Content

Chayanun Kobkam
Jidapha Tinoi
Sila Kittiwachana


The alkali and alkali ethanolysis were used for pretreatment and delignification of rice straw. The combined hydrothermal- alkali method presented the high efficiency for removing the lignin. The pretreatment condition was optimized and achieved the highest of delignification (92.5%) under 30% (w/v) NaOH at a ratio of rice straw to alkali solution of 1 : 10 (w/v) at 121°C for 20 min. The highest yield of the remaining cellulose was 81.5% (w/w). The enzymatic hydrolysis of the rice straw cellulose was optimized for enhancement the digestibility via Response Surface Methodology (RSM). The cellulase activity, buffer solution, and hydrolysis time were evaluated. The optimum condition was cellulase activity at 935.18 U, 10 mL of buffer solution 10% (w/v) with hydrolysis time for 120 h, represented the maximum sugar yield with 136.6 g/L (0.54 g/g rice straw). The rice straw hydrolysate was further used as carbon source for microbial oil production by oleaginous yeasts.

Article Details

How to Cite
Kobkam, C., Tinoi, J., & Kittiwachana, S. (2018). Alkali Pretreatment and Enzyme Hydrolysis to Enhance the Digestibility of Rice Straw Cellulose for Microbial Oil Production. Applied Science and Engineering Progress, 11(4). Retrieved from
Research Articles


[1] Department of Alternative Energy Development and Efficiency. (2016, Jan.). Biomass Potential Reporting System in Thailand. Ministry of energy. Bangkok, Thailand [online]. Available:

[2] R. Zhao, Z. Zhang, R. Zhang, M. Li, Z. Lei, M. Utsumi, and N. Sugiura, “Methane production from rice straw pretreated by a mixture of acetic–propionic acid,” Bioresource Technology, vol. 101, pp. 990–994, Feb. 2010.

[3] J. Pérez, J. Muñoz-Dorado, T. de la Rubia, and J. Martínez, “Biodegradation and biological treatments of cellulose, hemicellulose and lignin: An overview,” International Microbiology, vol. 5, pp. 53–63, Jun. 2002.

[4] P. Kumar, D. M. Barrett, M. J. Delwiche, and P. stroeve, “Methods for pretreatment of lignocellulosic biomass for efficient hydrolysis and biofuel production,” Industrial and Engineering Chemistry Research, vol. 48, pp. 3713–3729, Mar. 2009.

[5] R. C. Kuhad, A. Singh, and K.-E. L. Eriksson, “Microorganisms and enzymes involved in the Degradation of plant fiber cell walls,” Advances in Biochemical Engineering/Biotechnology, vol. 57, pp. 45–125, 1997.

[6] K. Karimi, S. kheradmandinia, and M. J. Taherzadeh, “Conversion of rice straw to sugars by dilute-acid hydrolysis,” Biomass and Bioenergy, vol. 30, pp. 247–253, Mar. 2006.

[7] Y. Sun and J. Cheng, “Hydrolysis of lignocellulosic materials for ethanol production: A review,” Bioresource Technology, vol. 83, pp. 1–11, May. 2002.

[8] F. Monlau, C. Sambusiti, A. Barakat, M. Quéméneur, E. Trably, J.-P. Steyer, and H. Carrère, “Do furanic and phenolic compounds of lignocellulosic and algae biomass hydrolyzate inhibit anaerobic mixed cultures? A comprehensive review,” Biotechnology Advances, vol. 32, pp. 934–951, Sep.–Oct. 2014.

[9] B. J. Khawla, M. Sameh, G. Imen, F. Donyes, G. Dhouha, E. G. Raoudha, and N.-E. Oumèma, “Potato peel as feedstock for bioethanol production: A comparison of acidic and enzymatic hydrolysis,” Industrial Crops and Products, vol. 52, pp. 144–149, Jan. 2014.

[10] E. R. Easterling, W. T. French, R. Hernandez, and M. Licha, “The effect of glycerol as a sole and secondary substrate on the growth and fatty acid composition of Rhodotorula glutinis,” Bioresource Technology, vol. 100, pp. 356–361, Jan. 2009.

[11] C. Dai, J. Tao, F. Xie, Y. Dai, and M. Zhao, “Biodiesel generation from oleaginous yeast Rhodotorula glutinis with xylose assimilating capacity,” African Journal of Biotechnology, vol. 6, pp. 2130–2134, Aug. 2007.

[12] T. L. D. Silva, D. Feijão, J. C. Roseiro, and A. Reis, “Monitoring Rhodotorula glutinis CCMI 145 physiological response and oil production growing on xylose and glucose using multi-parameter flow cytometry,” Bioresource Technology, vol. 102, pp. 2998–3006, Feb. 2011.

[13] G. Vicente, L. F. Bautista, R. Rodríguez, F. J. Gutiérrez, I. Sádaba, R. M. Ruiz-Vázquez, S. Torres-Martínez, and V. Garre, “Biodiesel production from biomass of an oleaginous fungus,” Biochemical Engineering Journal, vol. 48, pp. 22–27, Dec. 2009.

[14] C. Sakdaronnarong, N. Srimarut, N. Lucknakhul, N. Na-songkla, and W. Jonglertjunya, “Two-step acid and alkaline ethanolysis/alkaline peroxide fractionation of sugarcane bagasse and rice straw for production of polylactic acid precursor,” Biochemical Engineering Journal, vol. 85, pp. 49–62, Apr. 2014.

[15] G. L. Miller, “Use of dinitrosalicylic acid reagent for dertermination of reducing sugar,” Analytical Chemistry, vol. 31, pp. 426–428, Mar. 1959.

[16] Forage Fiber Analyses (Apparatus, Reagents, Procedures, and Some Applications), Agriculture Handbook No. 379, United States Department of Agriculture (USDA), Washington, DC, 1970, pp. 1–20.

[17] L. J. Jönsson and C. Martín, “Pretreatment of lignocellulose: Formation of inhibitory byproducts and strategies for minimizing their effects,” Bioresource Technology, vol. 199, pp. 103–112, Jan. 2016.

[18] H. Tarkow and W. C. Feist, “A mechanism for improving the digestibility of lignocellulosic materials with dilute alkali and liquid ammonia,” Cellulases and Their Applications, vol. 95, pp. 197–218, Jun. 1969.

[19] M. J. Taherzadeh and K. Karimi, “Pretreatment of lignocellulosic wastes to improve ethanol and biogas production: A review,” International Journal of Molecular Sciences, vol. 9, pp. 1621–1651, Sep. 2008.

[20] M. Zeng, N. S. Mosier, C.-P. Huang, D. M. Sherman, and M. R. Ladisch, “Microscopic examination of changes of plant cell structure in corn stover due to hot water pretreatment and enzymatic hydrolysis,” Biotechnology and Bioengineering, vol 97, pp. 265–278, Jun. 2007.

[21] I. Kim and J.-I. Han, “Optimization of alkaline pretreatment conditions for enhancing glucose yield of rice straw by response surface methodology,” Biomass and Bioenergy, vol. 46, pp. 210–217, Nov. 2012.

[22] N. Rahnama, S. Mamat, U. K. M. Shah, F. H. Ling, N. A. A. Rahman, and A. B. Ariff, “Effect of alkali pretreatment of rice straw on cellulase and xylanase production by local Trichoderma harzianum SNRS3 under solid state fermentation,” Bioresources, vol. 8, pp. 2881–2896, 2013.

[23] R. A. Silverstein, Y. Chen, and R. R. Sharma-Shivappa, “A comparison of chemical pretreatment methods for improving saccharification of cotton stalks,” Bioresource Technology, vol. 98, pp. 3000–3011, Nov. 2007.

[24] R. Sun, J. M. Lawther, and W. B. Banks, “Influence of alkaline pre-treatments on the cell wall components of wheat straw,” Industrial Crops and Products, vol. 4, pp. 127–145, Jul. 1995.

[25] C. Tengborg, K. Stenberg, M. Galbe, G. Zacchi, S. Larsson, E. Palmqvist, and B. Hahn-Hägerdal, “Comparison of SO2 and H2SO4 impregnation of softwood prior to steam pretreatment on ethanol production,” Applied Biochemistry and Biotechnology, vol. 70–72, pp. 3–15, Mar. 1998.

[26] H. T. Tan, K. T. Lee, and A. R. Mohamed, “Pretreatment of lignocellulosic palm biomass using a solvent-ionic liquid [BMIM]Cl for glucose recovery: An optimisation study using response surface methodology,” Carbohydrate Polymers, vol. 83, pp. 1862–1868, Feb. 2011.

[27] A. M. Joglekar and A. T. May, “Product excellence through design of experiments,” Cereal Food World, vol. 32, pp. 857–868, May 1987.

[28] J.-W. Kim, K. S. Kim, J.-S. Lee, S. M. Park, H.-Y. Cho, J. C. Park, and J. S. Kim, “Twostage pretreatment of rice straw using aqueous ammonia and dilute acid,” Bioresource Technology, vol. 102, pp. 8992–8999, Oct. 2011.

[29] X. Yu, Y. Zheng, K. M. Dorgan, and S. Chen, “Oil production by oleaginous yeasts using the hydrolysate from pretreatment of wheat straw with dilute sulfuric acid,” Bioresource Technology, vol. 102, pp. 6134–6140, May 2011.

[30] X.–F. Chen, C. Huang, X.–Y. Yang, L. Xioang, X.-D. Chen, and L.-L. Ma, “Evaluating the effect of medium composition and fermentation condition on the microbial oil production by Trichosporon cutaneum on corncob acid hydrolysate,” Bioresource Technology, vol. 143, pp. 18–24, Sep. 2013.

[31] W. Liu, Y. Wang, Z. Yu, and J. Bao, “Simultaneous saccharification and microbial lipid fermentation of corn stover by oleaginous yeast Trichosporon cutaneum,” Bioresource Technology, vol. 118, pp. 13–18, Aug. 2012.

[32] F. Deeba, V. Pruthi, and Y. S. Negi, “Converting paper mill sludge into neutral lipids by oleaginous yeast Cryptococcus vishniaccii for biodiesel production,” Bioresource Technology, vol. 213, pp. 96–102, Aug. 2016.