Tuesday, April 30, 2013
Exhibit Hall
The importance of the biofuels commercial production is sustained mainly in one of the recent worldwide challenges, that is the reduction of pollutant gas emissions by the reduction of the fossil fuels dependence. In the case of Brazil, the technology of ethanol production is very well consolidated. In this context, it is crucial the development of second generation ethanol production technology from sugars constituents of cellulosic and hemicellulosic fractions of vegetable biomass. One obstacle for the attainability of this technology is de development of effective and low cost hydrolysis processes able to deconstruct the vegetal polymeric matrix for the release of its fermentable carbohydrates represented by the sugars C6 and C5. Another critical point is the use of all carbohydrates constituents of the vegetable biomass, in particular pentoses such as xylose and arabinose. In this context, the present study evaluates the assimilation of arabinose by Candida guilliermondii during fermentation of sugarcane bagasse hemicellulosic hydrolysate employing fermenter of 2.4 and 16L (KLa = 15 h-1). It was observed that unlike for the xylose consumption, arabinose was slowly assimilated by yeast and its consumption was simultaneous with xylose. The scale-up process from 2.4 to 16L favored arabinose consumption which resulted in increased cell production. Considering that different factors contribute to this behavior as the type of transport involved in the metabolism of these pentoses, presence of other compounds in the hydrolysate such as acetic acid and phenols, more research is needed to better understand this metabolism.
Acknowledgments: FAPESP, CAPES, CNPq