Metabolic Pathway Engineering in Cyanobacteria for Biohydrogen Production

Switching to cleaner and greener energy sources is now imperative to meet the ever-increasing global demands while keeping the carbon footprint low to minimize the impacts of climate change. Cyanobacteria, having higher photosynthetic efficiency and biomass productivity among all terrestrial plants, are robust cellular factories with extraordinary potential to produce biohydrogen. Commercial biohydrogen production using cyanobacteria is still at the nascent stage due to several challenges, including (1) cyanobacteria’s hydrogenase sensitivity to oxygen, (2) low hydrogenase efficiency, (3) competing pathways and metabolism flux, (4) photobioreactor design and scale-up, (5) strain stability, (6) multi-parameters optimization, (5) regulatory and ethical issues with genetic transformation, and (6) techno-economic challenges. However, metabolic pathway engineering techniques could improve the low biohydrogen yield in cyanobacteria. In cyanobacteria farming, along with genetic modifications, optimizing the various cultivation parameters (nutrients, reactor design, strain selection, air flow, temperature, and light intensity) could help enhance biomass productivity, leading to higher biohydrogen production. This chapter discusses various molecular approaches and genetic engineering techniques to overcome the challenges mentioned above. In the future, Artificial Intelligence and mathematical models can help optimize multiple parameters to enhance the growth of genetically modified cyanobacteria that can pave the path to commercial scale biohydrogen production using cyanobacteria.