Biological hydrogen with industrial potential: Improvement and prospection in biohydrogen production

Hydrogen is an important industrial material and ideal secondary energy. It is widely used in petrochemical, electronics, metallurgy, food processing, fine organic synthesis, and clean energy. Currently, most of the hydrogen consumed comes from reforming fossil fuels, which results in significant emissions. In comparison, biohydrogen production is environmentally friendly and green, without additional carbon emissions. However, until now, the biohydrogen production system is relatively unstable, hindering its industrialization. Therefore, in this review, the key problems in biohydrogen production, including current measures from the aspects of hy-drogenase, hydrogen-producing organisms, hydrogen-evolving reactions, biohydrogen-producing culture and production systems, are summarized. It is concluded that a single microbial strain or hydrogen production method seems difficult for stable production. Instead, coupling hydrogen production with organic waste treat-ment and multi-type combination is an economically feasible way for scale production, which will be based on suitable waste and depend on the robust strains and appropriate microbial communities.