Using response-surface methodology to evaluate xylitol production by Candida guilliermondii by fed-batch process with exponential feeding rate

摘要

Xylitol production by Candida guilliermondii FTI 20037 from sugarcane bagasse hydrolysate by a fed-batch process using an exponential feeding rate was evaluated. A factorial design was employed to study the effects of the xylose concentration in thefermenter (S0) and the xylose concentration in the feeding solution (Si) upon the xylitol/xylose yield coefficient (YP/S) and the xylitol concentration (Cp). None of the variables had a significant effect on YP/S, yet their effects on Cp were significant. Response-surface methodology gave a polynomial model for Cp at the 95% confidence level: Cp = 15.896 - 1.410S0- + 0.487Si + 0.032S02. The best experimental Cp achieved was 44 g/litre, with YP/S = 0.78 g/g and volumetric productivity 0.62 g/litre per hour; Cp was only 37 g/litre under the conditions predicted to be optima by the model.