Hydrogen fermentation is a very complex process and is greatly influenced by many factors. Previous studies have demonstrated that temperature, pH and substrate are important factors controlling biological H(2) Production. Response surface methodology with central composite design was used in this study to optimize H(2) production from glucose by an anaerobic culture. The individual and interactive effects of pH, temperature and glucose concentration on H(2) production were also evaluated. The optimum conditions for maximum H(2) yield of 1.75 mol-H(2) mol-glucose(-1) were found as temperature 38.8 degrees C, pH 5.7 and glucose concentration 9.7 g L(-1). The linear effects of temperature and pH as well as their quadratic effects on H(2) yield were significant, while the interactive effects of three parameters were minor. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.