Tuesday, April 20, 2010
11-37

Optimization of enzymatic hydrolysis and fermentation of SO2- steam-exploded giant bamboo for bioethanol production by xylose-fermenting yeast Saccharomyces  cerevisiae Y294-X-1-Proto

María P. García-Aparicio1, Eugene Van Resburg1, Wilson Parawira1, W. H. van Zyl2, and J.F. Gorgens1. (1) Process Engineering, Stellenbosch University, Private Bag X1 Matieland, Stellenbosch, 7602, South Africa, (2) Microbiology, University of Stellenbosch, De Beer Street, Stellenbosch, South Africa

Cost-effective biological saccharification of nonfood lignocellulosic biomass is vital to the establishment of a carbohydrate economy for the obtention of energy-related end products such as bioethanol. There is a growing interest in the cultivation of bioenergy crops to find the envisioned development of biofuels during the next decades. Perennial herbaceous grasses such as bamboo can play an important role in this capacity. Steam explosion SO2-catalysed (200 °C for 6 min at a catalyst concentration of 3% (w/w)) was shown to effectively hydrolyze the hemicellulose in giant bamboo with minimal byproducts formation and to serve as an effective pre-treatment for the enzymatic hydrolysis of cellulose. Up to 75% of the glucan from the remaining water-insoluble solids (WIS) was digested to glucose with a standard mixture of cellulase supplemented with β-glucosidase.
In this work, the effect of different commercial cellulases and the additional effect of a non-cellulolytic enzyme, xylanase, on final sugars yield will be evaluated by response surface technology. Besides, the effects of other paramaters such as temperature and total solids loading will be also statiscally studied. Additionally, simultaneous saccharification and fermentation will be conducted under the optimum conditions previously obtained to assess the ethanol production yield and productivity by the yeast Saccharomyces  cerevisiae Y294-X-1-Proto, which is able to coferment  sugars derived from hemicellulose and cellulose.


Web Page: sun025.sun.ac.za/portal/page/portal/Engineering/Process%20Engineering/English/Research/Environmental%20and%20Ener