Evaluation of nutrient supplementation to charcoal-treated and untreated rice straw hydrolysate for xylitol production by Candida guilliermondii.

摘要

The effect of supplementing charcoal-treated and untreated rice straw hemicellulose hydrolysates with ammonium sulfate, calcium chloride and rice bran extract on xylitol production by Candida guilliermondii in culture media was evaluated. The results showed that nutrient supplementation did not affect xylose consumption, but in media without nutrient addition, both xylitol production and cell growth were favoured. After 96 h of bioconversion without nutrients, xylitol concentration was 40 g/litre in the charcoal-untreated hydrolysate and 59 g/litre in the charcoal-treated hydrolysate. However, addition of nutrients resulted in xylitol concentration of about 30 g/litre in both charcoal-treated and untreated hydrolysates. It is concluded that rice straw hemicellulose hydrolysate treated with activated charcoal is a cheap source of xylose and other nutrients for xylitol production by C. guilliermondii. Nutrient supplementation to rice straw hemicellulose hydrolysate media is unnecessary..