Renewable hydrogen production by dark-fermentation: Current status, challenges and perspectives

Global urbanization has resulted in amplified energy and material consumption with simultaneous waste generation. Current energy demand is mostly fulfilled by finite fossil reserves, which has critical impact on the environment and thus, there is a need for carbon-neutral energy. In this view, biohydrogen (bio-H-2) is considered suitable due to its potential as a green and dependable carbon-neutral energy source in the emerging 'Hydrogen Economy'. Bio-H-2 production by dark fermentation of biowaste/biomass/wastewater is gaining significant attention. However, bio-H-2 production still holds critical challenges towards scale-up with reference to process limitations and economic viabilities. This review illustrates the status of dark-fermentation process in the context of process sustainability and achieving commercial success. The review also provides an insight on various process integrations for maximum resource recovery including closed loop biorefinery approach towards the accomplishment of carbon neutral H-2 production.

Automated summary

Global urbanization has led to increased energy and material consumption, along with a rise in waste generation. The demand for carbon-neutral energy sources like biohydrogen is on the rise, but challenges in production scale-up, process limitations, and economic viability remain. Integration of processes and closed loop biorefinery approaches are being explored for achieving carbon neutral hydrogen production.