Use of dry yeast biomass as a new approach for detoxification of hemicellulosic hydrolysates aiming to xylitol production

Abstract

The presence of toxic compounds in hemicellulosic hydrolysates is a bottleneck for biotechnological processes, such as xylitol production. In our work, a new approach was proposed for hemicellulosic hydrolysates detoxification by using the residual dry yeast biomass (DYB) from xylitol production bioprocess. Candida tropicalis biomass was recovered from fermentation process of a medium based on sugarcane bagasse and straw hemicellulosic hydrolysate (SBSH). The effects of influent variables on detoxification performance were investigated, and the removal of phenolic compounds, acetic acid, furfural and 5-hydroxymethylfurfural reached up to, respectively, 27.0 %, 26.7 %, 27.5 %, and 25.8 %. By using the SBSH detoxified at conditions of highest phenolics removal, fermentations (initial xylose concentration of 52 g L−1) were performed for xylitol production, resulting in a yield of 0.79 gg-1 and 86 % of conversion efficiency. Thus, the use of residual DYB is a potential alternative for detoxification of hemicellulosic hydrolysates, since recycling the biomass could reduce the expenditures with adsorbents.