The advances in bio-hydrogen production by two steps of dark and photo-fermentation
暗发酵-光发酵两阶段联合生物制氢技术研究进展

With the increasing of energy shortage and environmental problems caused by burning fossil fuels, hydrogen, as a clean and renewable energy has gained special attention. Compared with thermochemical and electrochemical hydrogen production, bio-hydrogen production has a lot of advantages, such as ambient reaction conditions, low consumption and environmentally friendly. Therefore, it was considered as a promising technology. Bio-hydrogen production usually undergoes two stages, i.e., dark fermentation and light fermentation. In dark fermentative stage, waste organic materials can be converted to hydrogen by bacteria, and leave some by-products, such as organic acids. The photosynthetic bacteria can decompose organic acids and release hydrogen by using light energy and nitrogenase in a photo fermentation process. Thus, combining these two kinds of hydrogen production methods can improve the utilization rate of waste organic material. This review is based on the development of dark and photo two-stage fermentation in recent years. It was elaborated mainly from the following aspects: mechanism of two-stage hydrogen production, main influence factors, kinds of two steps bio-hydrogen production (sequential dark and photo-fermentation & combined dark and photo-fermentation), and the facing challenges.