Xylitol production by Candida guillermondii as an approach for the utilization of agroindustrial residues

Different substrates based on hydrolyzed hemicellulosic fractions of agroindustrial residues were used for xylitol production by Candida guilliermondii FTI 20037 under semi-aerobic conditions. Batch fermentation performances were characterized and compared with those attained in a synthetic medium using -xylose as a major carbon source. For all media tested, simultaneous utilization of hemicellulosic sugars (glucose and xylose) was observed and the highest substrate uptake rate was attained in sugar cane bagasse medium. Increased xylitol concentrations (40 g/litre) were achieved in synthetic and rice straw-media, although the highest xylitol production rate was obtained in sugar cane bagasse hydrolysate. These results show that both hydrolysates can be converted into xylitol with satisfactory yields and productivities.