Biohydrogen—A Green Fuel for Sustainable Energy Solutions

Energy plays a crucial role in the sustainable development of modern nations. Today, hydrogen is considered most promising alternative fuel as it can be generated from clean and green sources. Moreover, an efficient energy carrier because burning only generates water byproduct. Currently, natural gas. However, produced using other methods, i.e., physicochemical, thermal, biological. The biological method more environmentally friendly pollution free. This paper aims to provide updated review biohydrogen production via photofermentation, dark fermentation, microbial electrolysis cells different waste materials feedstocks. Besides, nanotechnology enhancing examined. Under anaerobic conditions, during conversion organic substrate into acids fermentative bacteria carbon dioxide photofermentative bacteria. Different factors that enhance these organisms, either combined or sequentially, photofermentation processes, are examined, effect each factor on efficiency reported. A comparison between two-stage processes also presented.