Bioethanol Production from Enzymatically Saccharified Sunflower Stalks Using Steam Explosion as Pretreatment

Authors: Pilanee Vaithanomsat, Sinsupha Chuichulcherm, Waraporn Apiwatanapiwat

Abstract:

Sunflower stalks were analysed for chemical compositions: pentosan 15.84%, holocellulose 70.69%, alphacellulose 45.74%, glucose 27.10% and xylose 7.69% based on dry weight of 100-g raw material. The most optimum condition for steam explosion pretreatment was as follows. Sunflower stalks were cut into small pieces and soaked in 0.02 M H2SO4 for overnight. After that, they were steam exploded at 207 C and 21 kg/cm2 for 3 minutes to fractionate cellulose, hemicellulose and lignin. The resulting hydrolysate, containing hemicellulose, and cellulose pulp contained xylose sugar at 2.53% and 7.00%, respectively.The pulp was further subjected to enzymatic saccharification at 50 C, pH 4.8 citrate buffer) with pulp/buffer 6% (w/w)and Celluclast 1.5L/pulp 2.67% (w/w) to obtain single glucose with maximum yield 11.97%. After fixed-bed fermentation under optimum condition using conventional yeast mixtures to produce bioethanol, it indicated maximum ethanol yield of 0.028 g/100 g sunflower stalk.

Keywords: Enzymatic, steam explosion, sunflower stalk, ethanol production.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1054974

References:

[1] Sharma, S.K. et al. (2002) Enzymatic saccharification of pretreated sunflower stalks. Biomass and Bioenergy. 23: 237-243.
[2] Marechal, V. and Rigal, L. (1999) Characterization of by-products of sunflower culture-commercial applications for stalks and heads. Industrial Crops and Products. 10: 185-200.
[3] Sharma, S.K., Kalra, K.L. and Kocher, G.S. (2004) Fermentation of enzymatic hydrolysate of sunflower hulls for ethanol production and its scale up. Biomass and Bioenergy. 27: 399-402.
[4] Schandrel, S.H. (1970) Tannins and related phenolics, in methods in food analysis. Academic Press, New York.
[5] Khristova, P., Yossifov, N. and Gabir, S. (1996) Particle board from sunflower stalks: preliminary trials. Bioresource Technology. 58: 319- 321.
[6] Hang, Y.D. and Woodams, E.E. (2001) Enzymatic production of reducing sugars from corn cobs. Lebensm.-Wiss. U.-Technol. 34: 140- 142.
[7] Punsuvon,V., Vaithanomsat, P., Pumiput, P., Janthranurak, S. and Anpanurak, W. (2005) Fractionation of chemical components of oil palm trunk by steam explosion for xylitol and alcohol production. The Proceedings for 13th International Symposium on Wood, Fibre and Pulping Chemistry (ISWFPC). Auckland, New Zealand.