A hydrogen producing strain F.P 01 was newly isolated from cow dung sludge in an anaerobic bioreactor. The strain F.P 01 was a mesophilic and facultative anaerobic bacterium, which exhibited gram-negative staining in both the exponential and stationary growth phases, and a regular long rod-shaped bacteria with the size of 0.6-0.9 mu m x 1.2-2.5 mu m, and also could biodegrade a variety of carbohydrates such as glucose, xylose, maltose, etc. The effects of important process parameters on hydrogen producing of F.P 01 were further investigated from hydrogen fermentation of maltose by strain F.P 01, including substrate concentration, medium pH, etc. And the results showed that hydrogen production potential and hydrogen production rate from maltose of this strain F.P 01 was180 mLH(2)/g-maltose and 4.0 mLH(2)/h, respectively. The corresponding hydrogen concentration of 58-73% was also be observed. Both butyric acid and acetic acid as main by-product was left in the reactor. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.