Effects of oxygen and nutrients on xylitol and ethanol production in sugarcane bagasse hydrolyzates

The influence of oxygen and nutrient supplementation on xylitol and ethanol production in a synthetic medium and sugarcane bagasse hydrolyzates using Candida tropicalis IEC5-ITV and Saccharomyces cerevisiae ITV01- RD was investigated for evaluation of bioconversion of pentoses and hexoses present in the lignocellulosic biomass. The best oxygen transfer rate (56.05 mg of O-2/L/h) and xylitol and ethanol yields (0.67 and 0.47 g/g, respectively) were obtained in a synthetic medium. A yeast extract had a positive effect on xylitol and ethanol production (0.64 and 0.44 g/g, respectively) at a concentration of 1 g/L. C. tropicalis and S. cerevisiae exhibited not previously observed morphological changes depending on the nutrient composition. Use of sugarcane bagasse hydrolyzates requires a good supply of oxygen and addition of a yeast extract to improve xylitol and ethanol production.