Biohydrogen Production with Photosynthetic Microorganisms (Microalgae, Cyanobacteria, Purple Bacteria): Opportunities and Constraints

The widespread use of hydrogen as a biofuel will provide great support in combating the climate crisis and achieving the 2050 goals by minimizing the use of fossil resources. In comparison to chemical-based hydrogen production methods, microalgae-based biohydrogen production can be accepted the most eco-friendly approach. Microalgae-derived hydrogen is a more cost-effective, sustainable bioprocess, does not contain toxic chemicals, and provides efficient energy conversion. On the other hand, the commercialization of microalgal biohydrogen production is still in its infancy and there are some bottlenecks to overcome. Increasing the advanced PBR designs by utilizing new-generation technologies, increasing biomass productivity and energy efficiency by using genetic engineering tools, adopting a biorefinery approach and determining the environmental, social, and economic footprints of the process by life cycle assessment, increasing the number of scientific studies investigated scale-up strategies in indoor and outdoor based are innovative approaches that will increase the commercialization potential of microalgal biohydrogen production strategies. The mechanism of biohydrogen production from microalgae with various approaches, microalgal culture techniques from laboratory to commercial scale, constraints in the commercialization of biohydrogen, life cycle assessment of biohydrogen production, and association of biohydrogen with sustainable development goals have all been comprehensively discussed in this chapter.