Estudo da produção de xilitol por Meyerozyma caribbica UFMG08 a partir da otimização do processo fermentativo utilizando resíduos agroindustriais

Abstract

Xylitol is a natural sweetener, anti cariostatic, used mainly in the food and pharmaceutical industries. The economic value allied to various applications boost biotech research to increase production. A viable alternative is the production by xylose fermentation present in many industrial residues using yeasts. The aim of this work was to select a yeast with high potential for xylitol production and optimize this production in culture medium formulated with presscake hemicellulose hydrolyzate and brewer´s yeast extract. From Applied Microbiology Laboratory of yeast bank UFMG seven strains were tested, and selected the one with best fermentation parameters for xylitol production, Meyerozyma caribbica UFMG08. Three optimization processes were conducted: Fractional Factorial (DFF) and the Response Surface Methodology (RSM). The DFF to assess which factors (aeration, xylose concentration, nitrogen source and concentration of the nitrogen source) and their levels result or larger fermentation parameters for the xylitol production and the DCCR to establish an optimum point to xylitol production from predictive mathematical models. The optimization process showed that factors such as aeration and interaction of factors such as aeration, the nitrogen source and concentration of the nitrogen source influence on productive parameters for obtaining xylitol. Separately, the type of nitrogen source (commercial or resulting from brewer residue) did not interfere in the xylitol production, may be used that obtained from industrial waste without changes in production. From the optimization was increased by 13% xylitol production, increasing 60,04g/l, sugars conversion efficiency xylitol 0,79g/g and productivity 0.83g/l. This study opens up prospects for the biotechnological use of yeasts for production of xylitol process and to the use of agro-industrial wastes for the formulation of the culture medium.