Klebsiella pneumoniae ECU-15 (EU360791), which was isolated from anaerobic sewage sludge, was investigated in this paper for its characteristics of fermentative hydrogen production. it was found that the anaerobic condition favored hydrogen production than that of the micro-aerobic condition. Culture temperature and pH of 37 degrees C and 6.0 were the most favorable for the hydrogen production. The strain could grow in several kinds of monosaccharide and disaccharide, as well as the complicated corn stalk hydrolysate, with the best results exhibited in glucose. The maximum hydrogen production rate and yield of 482 ml/l/h and 2.07 mol/mol glucose were obtained at initial glucose concentration of 30 g/L and S g/L, respectively. Fermentation results in the diluent corn stalk hydrolysate showed that cell growth was not inhibited. However, the hydrogen production of 0.65 V/V was relatively lower than that of the glucose (1.11 V/V), which was mainly due to the interaction between xylose and glucose. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.