Microbial conversion of arabinose and xylose to hydrogen by a newly isolated Clostridium sp. No. 2.

For 24 h at pH 6.0 and 36 °C, Clostridium sp. No. 2, isolated from termites, converted arabinose and xylose to hydrogen with yields of 14.55 and 13.73 mmol/g of substrate consumed, respectively. These yields were greater than the maximum value of 11.07 mmol/g of glucose consumed in 1 L of batch culture with 10 g of each substrate. The organism produced hydrogen from 45 g of glucose and xylose in 1 L of culture with a total accumulation of 380.6 mmol from glucose and 479.0 mmol from xylose, at a conversion rate of 270.9 mmol/g of dry cells from glucose and 405.9 mmol/g of dry cells from xylose. Hydrogen was produced at a maximum evolution rate of 27.2 mmol/h after 8 h of incubation with glucose and of 28.6 mmol/h after 6 h of incubation with xylose.Key words: hydrogen production, xylose, arabinose, Clostridium sp. No. 2.