As a sustainable biofuel feedstock, marine algae have superior aspects to terrestrial biomass such as less energy and water requirement for cultivation, higher CO(2) capture capacity, and negligible lignin content. In this study, various marine algae were tested for fermentative hydrogen production (FHP). Among them, Laminaria japonica exhibited the best performance, showing the highest H(2) yield of 69.1 mL H(2)/g COD(added). It was attributed to its high carbohydrate content and main constituents of polysaccharides, laminarin and alginate, which were found to posses higher H(2) production potential than agar and carrageenan. To enhance the H(2) production from L japonica, thermal pretreatment was applied at various conditions. At 170 degrees C and 20 min. H(2) yield was maximized to 109.6 mL H(2)/g COD(added). The experimental results suggested that marine algae, especially L japonica, could be used for FHP, and future works would be focused on gaining more energy from the H(2) fermentation effluent. (C) 2010 Elsevier Ltd. All rights reserved.