Effect of Thermo-Chemical Pretreatment on Bioethanol Production from Corncobs

Abstract:

Currently, ethanol has gained significance since it is substantially used as an alternative biofuel. It can be produced by agro-industrial residuals such as corncobs. In ethanol production, hemicellulose and lignin are inhibitors of the enzymatic hydrolysis between cellulase and cellulose. They must be removed during in the pretreatment stage. In this research H2SO4 and NaOH were used as pretreatment solution at high temperature. The temperature were varied for 120 to 170 °C. The result showed that the optimal pretreatment condition of corncobs was using 2% (v/v) NaOH for 24 hr digestion in 1% (v/v) H2SO4 and then heating at 170 °C for 5 min. At this condition, the cellulose content of corncobs increased from 66.52% (untreated) to 92.25% (pretreated). Enzyme digestion of pretreated corncobs at an optimum condition yielded the reducing sugar level of 8.74 g/L. The optimum conditions were achieved at cellulase loading of 10 FPU/g and digestion time of 4 hr. Finally, the reducing sugar solution of 5 g/L was fermented with Zymomonas mobilis TISTR405 at 30°C and pH 5.0 for 48 hr, yielding ethanol of 1.8 g/l or 35.93% of the theoretical ethanol yield.

• Periodical: Advanced Materials Research (Volumes 347-353)
• Pages: 2532-2535
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.347-353.2532
• Online since: October 2011
• Authors: Poramate Sukchum, Warawut Chulalaksananukul, Orathai Chavalparit
• Keywords: Cellulolysis, Lignocellulosic Ethanol, Pre-Treatment, Zymomonas Mobilis

References

[1] Y. Zheng, Z. Pan and R. Zhang: Overview of biomass pretreatment for cellulosic ethanol production, Int J Agric & Biol Eng, Vol. 2(3) (2009), p.51－68.

[2] S. S. Danielle, C. C. Anna, P. R. Kelly, C. C. Luís and P. J. Nei: Ethanol Production from Sugarcane Bagasse by Zymomonas mobilis Using Simultaneous Saccharification and Fermentation (SSF) Process, Appl Biochem Biotechnol Vol. 161 (2010), p.93–105.

DOI: 10.1007/s12010-009-8810-x

[3] M. B. Stickle: Nature Reviews Genetics Vol. 9 (2008), pp.433-443.

[4] M. J. Antal, S. G. Allen, X. Dai, B. Shimizu, M. S. Tam and M. Gronli: Attainment of the theoretical yield of carbon from biomass, Ind. Eng. Chem. Res Vol. 39 (2000), p.4024–4031.

DOI: 10.1021/ie000511u

[5] B. C. Saha, B. S. Dien and R. J. Bothast: Fuel ethanol production from corn fiber: current status and technical prospects, Appl. Biochem. Biotechnol Vol. 70–72 (1998), p.115–125.

DOI: 10.1007/bf02920129

[6] B. C. Saha: Hemicellulose bioconversion, J. Ind. Microbiol. Biotechnol Vol. 30 (2003), p.279–291.

[7] J. Harris, A. Baker and J. Zerbe: Two-stage, dilute sulfuric acid hydrolysis of hardwood for ethanol production, Energy Biomass Wastes Vol. 8 (1984), p.1151–1170.

[8] A. Hendriks and G. Zeeman: Pretreatments to enhance the digestibility of lignocellulosic biomass, Bioresour. Technol Vol. 100 (2009), p.10–18.

DOI: 10.1016/j.biortech.2008.05.027

[9] W. C. Miller: Evaluation of Feedstocks for Cellulosic Ethanol and Bioproducts Production in the Northwest. Master of Science in Biological and Ecological Engineering, Oregon State University, (2010).

[10] P. Kahar, K. Taku and S. Tanaka: Enzymatic digestion of corncobs pretreated with low strength of sulfuric acid for bioethanol production, Journal of Bioscience and Bioengineering doi:10.1016/j.jbiosc.2010.05. 002. (2010).

DOI: 10.1016/j.jbiosc.2010.05.002

[11] X. Li, T. Kim and N. Nghiem: Bioethanol production from corn stover using aqueous ammonia pretreatment and two-phase simultaneous saccharification and fermentation (TPSSF), Bioresource Technology Vol. 101 (2010), p.5910–5916.

DOI: 10.1016/j.biortech.2010.03.015

[12] J. Swings and J. DeLey: Bacteriological Reviews, Baltimore Vol. 41 (1977), p.1–46.

[13] P. L. Rogers, K. J. Lee, M. L. and D. E. Skotinich: Tribe Advances in Biochemical Engineering Vol. 23 (1982), p.27–84.

[14] TAPPI: Method for determination of alpha-, beta- and gamma-cellulose in pulp, Technical Association of Pulp and Paper Industry (2001).

[15] T. K. Ghose: Pure & Applied Chemistry Vol. 59 (1987), p.257–268.

[16] M. C. Bertolini, J. R. Erlandes, C. Laluse: New yeast strains for alcoholic fermentation of high sugar concentration, Biotechnol Bioeng Vol. 13 (1991), p.197–202.

DOI: 10.1007/bf01025817

[17] V. S. Chang, W. E. Kaar, B. Burr and M. T. Holtzapple: Simultaneous saccharification and fermentation of lime-treated biomass, Biotechnology Letters Vol. 23 (2001), pp.1327-1333.

DOI: 10.1023/a:1010594027988