The influence of pH and dilution rate on continuous production of xylitol from sugarcane bagasse hemicellulosic hydrolysate by C-guilliermondii

Continuous fermentation of sugarcane bagasse hemicellulosic hydrolysate by the yeast Candida guilliermondii FTI 20037 was used for xylitol production from xylose. Experiments were carried out in a reactor with 1.25 1 of treated hydrolysate, at 30 degreesC and 300 rpm. A 2 2 full-factorial central composite design was employed for experimental study and analysis of the results. A statistical analysis of the results showed that the effects of the pH and dilution rate (D), the interactions between these variables and the second-order effect of D on the xylitol volumetric productivity (Q(p)) were significant at a 95% confidence level. The second-order effect of pH was also significant at a 90% confidence level. The k(L)a effect on the Q, was not significant. A volumetric productivity of 0.68 g/l h, representing 95.8% of the predicted value (0.72 g/l h), was obtained. (C) 2002 Elsevier Science Ltd. All rights reserved.