Production of xylitol by Candida peltata.

The ability of Candida peltata NRRL Y-6888 to ferment xylose to xylitol was evaluated under different fermentation conditions such as pH, temperature, aeration, substrate concentration and in the presence of glucose, arabinose, ethanol, methanol and organic acids. Maximum xylitol yield of 0.56 g g-1 xylose was obtained when the yeast was cultivated at pH 6.0, 28 degrees C and 200 rpm on 50 g L-1 xylose. The yeast produced ethanol (0.41 g g-1 in 40 h) from glucose (50 g L-1) and arabitol (0.55 g g-1 in 87 h) from arabinose (50 g L-1). It preferentially utilized glucose > xylose > arabinose from mixed substrates. Glucose (10 g L-1), ethanol (7.5 g L-1) and acetate (5 g L-1) inhibited xylitol production by 61, 84 and 68%, respectively. Arabinose (10 g L-1) had no inhibitory effect on xylitol production.