Screening of arabinose assimilating yeasts to use of sugar cane bagasse for production of bioproducts

Abstract

The need to increase production of ethanol the use of lignocellulosic materials as a source of fermentable sugars have been a good approach. In Brazil, the sugar cane bagasse is an abundant lignocellulosic material with great potential to be used as a primary source in the biorefineries. The lignocellulose is composed of lignin and sugars polymers, as cellulose and hemicellulose, composed by hexoses and pentoses. When hydrolyzed cellulose provides glucose, which can be fermented by conventional process, and the hemicellulose release pentoses such as xylose and arabinose, which is not fermented by Saccharomyces cerevisiae. Additionally , the ability to metabolize pentoses is not much explored among the microorganisms. From the perspective of a global demand for the maximum potential of the lignocellulose is strictly necessary microbiological fermentation of pentoses, including the L- arabinose, which is the third most abundant sugar in plant material. In this context, we propose a study of assimilation of L- arabinose and study of secreted metabolites by yeasts from the work collection of the Laboratory of Applied Biochemistry and Microbiology, IBILCE/UNESP, São José do Rio Preto (SP). In a previous study, 36 yeasts was cultured in YNB medium containing 2% L-arabinose as the carbon source revealed that 17 of them assimilate arabinose. Were also performed preliminary studies with high-performance liquid chromatography (HPLC), which indicated synthesis of ethanol, citric and lactic acid by the yeast and additional several other unidentified metabolites by the method used. Aiming to establish the potential of strains for utilization of arabinose for obtainment biomass and value-added products, it is proposed to continue the project to identify other compounds secreted and optimize it production by yeasts. (AU)