13-35: Evaluation of three varieties of forage sorghum biomass for biotechnological xylitol production

Tuesday, May 1, 2012
Napoleon Ballroom C-D, 3rd fl (Sheraton New Orleans)
Daniela L. S. Variz, Priscila V. Arruda and Maria das Grašas A. Felipe, Departamento de Biotecnologia, Escola de Engenharia de Lorena - USP, Lorena, Brazil
In Brazil, forage sorghum is a type of sorghum that is used as covering of the ground and production of silage. The characteristics of this biomass as lignocellulosic material contributes to the biotechnological exploitation for obtainment of economic and social interest products, like xylitol, a special sugar that is used in several industries segments. In the present work 3 varieties (A, B and C) of forage sorghum were evaluated for biotechnological production of xylitol by Candida guilliermondii. It was evaluated the chemical characterization of the varieties, acid hydrolysis, detoxification and fermentations of the hemicellulosic hydrolysates. For the chemical characterization of the 3 varieties, no relevant difference was verified in relation to the amounts of cellulose, hemicellulose and lignin fractions. However, the variety A showed to be more promising for the xylitol production as a function of the obtained maximum parameters (YP/S and QP). In this case the maximum values of xylitol yield and productivity was 0,35 g/g and 0.16 g/L.h-1 for the variety A, 0.25 g/g and 0.12 g/L.h-1 for the variety B and 0.17 g/g and 0.063 g/L.h-1 for the variety C. Consequently the maximum enzymatic activities for XR (0.25 U/mgprot) and XDH (0.17 U/mgprot) occurred in the fermentations carried out with the variety A, while for the others varieties it was not verified a correlation between fermentative parameters and the enzymatic activities.

Acknowledgments: CAPESP and CNPq.

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