Influence of biomass and nanoadditives in dark fermentation for enriched bio-hydrogen production: A detailed mechanistic review on pathway and commercialization challenges

Abstract

Modernization of lifestyle, industrialization, population has resulted in generation of huge amount of waste, with rich in organic and inorganic content. Waste biomass (agriculture, algae, sludge, livestock manure, plant source) are available in large quantity worldwide owing to their renewability. Biomass is processed via thermochemical, biological, electrochemical processes for value added products recovery. This review focuses mainly on bio-hydrogen production from biomass via dark fermentation. Dark fermentation of biomass results in hythane formation (i.e methane and hydrogen) apart from other gases. The parameters that influence dark fermentation mechanism are temperature, hydraulic retention time, pH, inoculum. The influence of these parameters on NADH and formate pathways defines the yield of bio-hydrogen. The major hindrances on commercialization of dark fermentation-based bio-hydrogen process is due to its storage and transport problems. Unlike commercial petrol-diesel, bio-hydrogen cannot be transported or stored for longer period, owing to its environmental concerns. This review paves way for further research on identifying genetic improvement strategies on microbes for better bio-hydrogen yield and developing bio-hydrogen storage and transport designs.