Emerging trends in role and significance of biochar in gaseous biofuels production

Transition from fossil fuels to non-conventional sources is needed to tackle the global energy crisis and environment related issues. Thus, the use of organic waste generated from various industrial sectors can help to produce gaseous fuels through anaerobic digestion, photo and dark fermentation, and other biochemical strategies. Current biogas and biohydrogen production practices are less efficient and require additional interventions for biofuel yield improvement. In this regard, adding biochar has shown to enhancing gaseous fuel yield by about 5%-400%, adsorbing inhibitors such as ammonia, pathogens, hydrogen sulfide, and activating gas-producing mesophilic and thermophilic microorganisms. This review provides recent updates and future perspectives associated with the effect of biochar on gaseous biofuel production and its underlying mechanism. Further, there is a need for establishing a circular bioeconomy approach for biochar production and utilization through a 'waste-chain', for which a techno-economic analysis and life-cycle assessment are required. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).