Xylitol production from corn fibre hydrolysates by a two-stage fermentation process

Pichia guilliermondii strain NRRL Y-12723 fermented mixtures of xylose and arabinose to form xylitol and arabitol. However, cultures grown on a mixtur e of glucose, xylose and arabinose, in ratios characteristic of corn fibre hydrolysates, preferentially utilised glucose and only slowly metabolised p entose sugars, with low yields of sugar alcohols. A two-stage, sequential f ermentation scheme for the production of xylitol and arabitol from a mixtur e of sugars was developed. Following glucose consumption, cells were remove d from mixed sugar cultures and replaced with cells from cultures grown on xylose alone. In the second fermentation stage, xylose and arabinose were s uccessfully fermented to xylitol and arabitol. Dilute acid hydrolysates of corn fibre were suitable substrates for the two-stage fermentation process, but only after treatment with a mixed-bed deionization resin. (C) 2000 Els evier Science Ltd. All rights reserved.