Strategies of detoxification and fermentation for biotechnological production of xylitol from sugarcane bagasse

Abstract

The aim of this study was to evaluate strategies of detoxification and fermentation of the hemicellulosic liquors obtained from sugarcane bagasse autohydrolysis, for the biotechnological production of xylitol. Different sequences of detoxification treatments were performed, and their effects on sugars loss and inhibitors removal were evaluated. Fermentation assays were accomplished with commercial xylose to selectthe best yeast(C. guilliermondii, C.tropicalis) and the fermentation conditions ofthe detoxified spent liquors. Detoxification through a sequence oftreatments, including Ca(OH)2, IR-120 resin, activated charcoal, and IRA-67 resin, practically removed all inhibitors from the hemicellulosic spent liquors. Maximal concentration of xylitol obtained was 32.0 g L−1 (C. tropicalis, xylose: 104.1 g L−1, yield: 0.46 g g−1, productivity: 0.27 g L−1 h−1). The technological parameters to obtain a detoxified spent liquor rich in xylose and its bioconversion to xylitol were determined