Photoautotrophic hydrogen production by eukaryotic microalgae under aerobic conditions

Area of Science:

• Biotechnology
• Microbiology
• Photosynthesis

Background:

• Eukaryotic algae and cyanobacteria traditionally produce hydrogen under anaerobic or limited aerobic conditions.
• Previous understanding deemed hydrogen production under aerobic conditions infeasible.

Purpose of the Study:

• To investigate hydrogen production in novel microalgal strains (Chlorella vulgaris YSL01 and YSL16) under aerobic conditions.
• To explore the upregulation of the hydrogenase gene (HYDA) and its enzymatic activity in these strains.

Main Methods:

• Cultivating novel microalgal strains (Chlorella vulgaris YSL01 and YSL16) under controlled aerobic conditions with continuous illumination.
• Utilizing dissolved oxygen regimes mimicking natural aquatic environments.
• Measuring hydrogenase gene (HYDA) expression and specific hydrogenase activity.

Main Results:

• Demonstrated significant upregulation of the hydrogenase gene (HYDA) in C. vulgaris YSL01 and YSL16.
• Confirmed enzymatic hydrogen production by these microalgal strains, even under atmospheric conditions.
• Showcased simultaneous hydrogen production through photosynthesis using CO2 as the sole carbon source.

Conclusions:

• Novel Chlorella vulgaris strains can produce hydrogen photoautotrophically under aerobic conditions.
• This finding challenges previous assumptions about hydrogen production limitations.
• Results have significant implications for algae-based photolysis and ecological hydrogen assessments.