Kinetic study and modeling of xylitol production using Candida tropicalis in different culture media using unstructured models

Abstract

Unstructured models for cell growth, xylose consumption and xylitol production were applied for to describe the fermentation kinetics of xylitol production using Candida tropicalis in synthetic medium,and in non-detoxified oil palm empty fruit bunch (OPEFB) hydrolysate at 100 mL flask scale. In synthetic medium, the experimental maximum specific growth rate (μmax) and the cell mass yield factor(YX/S) were closer to the results of the Tessier model than those of the Contois and Monod models. Whereas, in non-detoxified OPEFB hydrolyzate, these parameters were closer to the results of the Contois model than those of the Tessier and Monod models. According to the models’ results, xylitol is mainly produced during the cell growth phase. The Tessier model in synthetic medium and Contois model in non-detoxified OPEFB hydrolysate had a coefficient of variation in growth kinetics of 32 and 33%, respectively. The significance of this study lies in simplifying the fermentation process through an unstructured and non-segregated model using three events at the same time, cell growth, substrate consumption and metabolite production.