The green alga Chlamydomonas reinhardtii has the ability to photosynthetically produce molecular hydrogen (H(2)) under anaerobic conditions. It offers a biological route to renewable H(2) production from sunlight and water. Algal growth and H(2) production kinetics must be understood in order to determine appropriate system parameters and develop photo-bioreactors. Algal biomass should be grown efficiently and economically to attain the high cell densities necessary for H(2) production. The nutrient requirements and process conditions that encourage the growth of dense and healthy algal cultures were explored. Anaerobic conditions were imposed by sulphur deprivation, which requires an exchange of the algal growth medium by centrifugation or dilution. A tubular flow photobioreactor featuring a large surface-to-volume ratio was used to monitor and control the key parameters in the H(2) production process, including pH, dissolved oxygen, optical density, temperature, agitation and light intensity. A cumulative H(2) yield of 3.1 +/- 0.3 ml/l of culture was measured. Copyright (C) 2010, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.