A hydrogen producing strain newly isolated from anaerobic sludge in an anaerobic bioreactor, was identified as Clostridium beijerinckii Fanp3 by 16S rDNA gene sequence analysis and detection by BioMerieux Vitek. The strain could utilize various carbon and nitrogen sources to produce hydrogen, which indicates that it has the potential of converting renewable wastes into hydrogen. In batch cultivations, the optimal initial pH of the culture medium was between 6.47 and 6.98. Using 0.15 M phosphate as buffer could alleviate the medium acidification and improve the overall performance of C. beijerinckii Fanp3 in hydrogen production. Culture temperature of 35 degrees C was established to be the most favorable for maximum rate of hydrogen production. The distribution of soluble metabolic products (SMP) was also greatly affected by temperature. Considering glucose as a substrate, the activation energy (E.) for hydrogen production was calculated as 81.01 kcal/mol and 21.4% of substrate energy was recovered in the form of hydrogen. The maximal hydrogen yield and the hydrogen production rate were obtained as 2.52 mol/mol-glucose and 39.0 ml/g-glucose h(-1), respectively. These results indicate that C. beijerinckii Fanp3 is an ideal candidate for the fermentative hydrogen production. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.