Biohydrogen production from microalgae for environmental sustainability.

Area of Science:

• Biotechnology and Renewable Energy
• Environmental Science
• Biochemistry

Background:

• Hydrogen is a clean energy source crucial for global sustainability and mitigating climate change.
• Microalgae-based biohydrogen production is an attractive method for carbon neutrality and bioenergy sustainability.
• This review focuses on various mechanisms of biohydrogen generation from microalgae.

Purpose of the Study:

• To explore mechanisms of biohydrogen production from microalgae, including direct biophotolysis, indirect biophotolysis, photo fermentation, and dark fermentation.
• To summarize potential algal strains and key hydrogen-producing enzymes, particularly [Fe-Fe]-hydrogenases.
• To discuss factors affecting efficiency, enzyme sensitivity, and recent advancements in the field.

Main Methods:

• Review of existing literature on microalgae biohydrogen production mechanisms.
• Analysis of different fermentation pathways (photo vs. dark) and biophotolysis.
• Identification and comparison of hydrogen-producing enzymes ([Fe-Fe]-hydrogenases, [Ni-Fe]-hydrogenases, nitrogenases).

Main Results:

• Dark fermentation is generally more efficient and less dependent on sunlight than other methods.
• [Fe-Fe]-hydrogenases exhibit significantly higher activity compared to other hydrogen-producing enzymes.
• Sulfur deprivation is the most practical pathway for biohydrogen generation.

Conclusions:

• Microalgae hold significant potential for sustainable biohydrogen production.
• Addressing challenges like enzyme efficiency and oxygen sensitivity is key for future development.
• Advancements in genetic engineering, consortia, and nanomaterials offer promising avenues for optimization.