Fermentative Biohydrogen Fuel Production Utilizing Wastewater: A Review

Abstract

Currently, there is greater emphasis on using renewable energy sources as compared to conventional sources of energy. Biohydrogen, a renewable energy source, serves as a promising alternative to fossil fuel-based energy sources. The demand for sustainability is met by producing biohydrogen with the use of wastewater as a substrate. This review article focuses on different ways of biohydrogen production from wastewater with the help of microorganisms, such as light independent processes like dark fermentation and light dependent processes like photo-fermentation, bio-photolysis (direct and indirect) and integrated processes like sequential fermentation and combined fermentation. The biochemical pathways, microorganisms employed, specific pretreatment techniques, and efficiency of the biohydrogen production methods by H2 yield and H2 production rate from different wastewater sources are also discussed. Different methods like dark fermentation, photo-fermentation and integration of these types using various substrates have been put forth. This review article also explains the various pretreatment methods of wastewater like physical, chemical, biological, and mechanical which is essential when using wastewater as substrate in order to increase biohydrogen production. The important characteristics that can influence hydrogen production, such as pH, temperature, hydraulic retention rate, and organic loading rate are also mentioned. In addition, the advantage and drawbacks of biohydrogen production, as well as the potential advancements presently being investigated to tackle these challenges are also highlighted. Therefore, many techniques and technologies are currently adopted to enhance the production of biohydrogen, which will lead to a sustainable environment.