Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 6, 1999
Publication Date: N/A
Technical Abstract: The production of xylitol by fermentation has become attractive because of the problems associated with its production chemically. Xylitol can be used as a natural food sweetener, a dental carries reducer, and a sugar substitute for diabetics. 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. A maximum xylitol yield of 0.56 g/g xylose was obtained when the yeast was cultivated at pH 6.0, 28 deg C, and 200 rpm on 50 g/L xylose. The yeast produced ethanol (0.41 g/g in 40 h) from glucose (50 g/L) and arabitol (0.55 g/g in 87 h) from arabinose (50 g/L). It preferentially utilized glucose > xylose > arabinose from mixed substrates. Glucose (10 g/L), ethanol (7.5 g/L), and acetate (5 g/L) inhibited xylitol production by 61, 84, and 68%, respectively. Arabinose (10 g/L) had no inhibitory effect on xylitol production by the yeast. Problems and prospects of xylitol production by fermentation will be presented.