Waste to Sustainable Biohydrogen Production Via Photo-Fermentation and Biophotolysis ? A Systematic Review

Considering the environmental challenges humanity faces in 21st century, it is obvious that there an enormous need for change of global energy map. Under these circumstances, new sources and intermediates must be considered as options to limit greenhouse gases emissions mitigate climate crisis. Biohydrogen production one most appealing options, due hydrogen's multiple applications zero a fuel, empower future hydrogen circular economy. In this review article we focus on two methods are not widely used at industrial scale but have many possibilities growth margins: (a) photo-fermentation (b) bio photolysis. Both light dependent photobioreactors function produce significant amounts biohydrogen. Based extensive literature search systemic analysis findings, presentation different reactants, operating conditions biohydrogen productions, key factors effecting parameters were discussed. Temperature, pH, intensity photobioreactor operation design some define rates yields. Innovative solutions approaches presented including biotechnological genetic engineering modifications microorganisms, well combinations hybrid producing methods, especially dark photo fermentation. For implementing circular-economy, wastes explored potential feedstocks, overcoming major bottlenecks biophotolysis face transition sustainable economy,