Clostridium species for fermentative hydrogen production: An overview

Dark fermentation is considered as a promising method for sustainable hydrogen generation. Microorganisms play a pivotal role in hydrogen production efficiency. Strains from genus Clostridium have been the most widely detected and used microorganisms in dark fermentative hydrogen production. In this review, the characteristics of hydrogen-producing Clostridium species are introduced, including the metabolic pathways, hydrogen production performance, and substrate diversity. In addition, strategies for improving the hydrogen production by Clostridium species were extensively reviewed, and the promising applications of the fermentation system from the points of economic and environmental benefits were displayed. Finally, perspectives concerning the further application of hydrogen production by Clostridium species were proposed. Extensive studies demonstrate that Clostridium species are good candidates for fermentative hydrogen production with both high hydrogen yield and wide substrate range, but more efforts are still needed to ensure the efficient and stable operation of the system, and make the process economically applicable.