Purification and Crystallization of Xylitol from Fermentation broth of Corncob Hydrolysates

摘要

Xylitol, a five-carbon sugar alcohol, is a valuable sugar substitute, and widely used in pharmaceutical, odontological and food industry due to its interesting properties. In the past decades, the xylitol industry is growing rapidly and more attention has been focused on the xylitol purification which processed an important proportion of the whole industry. In our paper, the purification and crystallization of xylitol fermentation broth by a biotechnology using corncob hydrolysates as substance have been studied. Initial xylitol fermentation broth was decolored with actived carbon (1% M-1, 60℃, 165 rpm), desalted with combination of two ion-exchange resins (732 and D301), and residual sugars were separated with UBK-555(Ca2+). Then the solution was vacuum-concentrated up to supersaturation (750 g/L xylitol). After adding 1 % xylitol crystal seeds, the supersaturated solution was cooled to -20℃ for 48 h. The crystalline xylitol of regular tetrahedral shape whose purity (0.95) and crystallization yield (0.602) was obtained from the clarified xylitol fermentation broth. An intact, economical and environmental-friendly route of purification and crystallization of xylitol from fermentation of corncob hydrolysates was obtained, and its experimental procedure and data provided a sound basis for large-scale industrial production.