In the present work the hydrogenesis in the anaerobic alkalithermophilic bacterium Thermobrachium celere was studied. The impact of several factors on hydrogen production during glucose fermentation was investigated in batch conditions. The optimal hydrogen production occurred at pH(67 degrees C) 8.2 with phosphate buffer concentration of 50 mM. Hydrogen yield reached the highest value of 3.36 mol H(2)/mol glucose when the partial pressure in the gas headspace was reduced. Supplementation of nitrogen sources and iron affected hydrogen production. Under optimized conditions, the maximum H(2) accumulation and H(2) production rate were estimated to be respectively 124.3 mmol H(2)/l culture and 20.7 mmol H(2)/l/h. Considering the efficient and rapid hydrogen evolution, and the ability to grow in extreme environments, T. celere might be a good candidate for biohydrogen production in open (non-sterile) bioprocess system. (C) 2011 Elsevier Ltd. All rights reserved.