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.

The Role of Microbial Diversity in Lignocellulosic Biomass Degradation: A Biotechnological Perspective

“…In industrial biocatalysis, ligninases are gaining traction as biocatalysts for several oxidation reactions. Their high redox potential allows ligninases to convert recalcitrant substrates under mild conditions [83, 84]. Recent examples include ligninase‐catalyzed degradation of polycyclic aromatic hydrocarbons [16], production of drug metabolites, and derivation of bio‐based chemicals from lignin [85].…”

Levels of microbial diversity affect the stability and function of dark fermentation bioreactors

“…Dark fermentation consortia are derived from anaerobic digestion communities in which hydrogen-producing bacteria are selected by using aggressive pretreatments and strictly controlling culture conditions (Wang and Yin, 2017). In hydrogen-producing reactors, instability, invasion by lactic acid bacteria (LAB) and low yield are still unresolved issues and proposed causes might involve biodiversity loss and competitive interactions (Castellóet al, 2020;Thulasisingh et al, 2023). Thus, understanding the ecological mechanisms that underlie population dynamics in hydrogen-producing consortia can provide insights into predicting and controlling communitylevel properties.…”