Photosynthetic CO₂ Conversion to Fatty Acid Ethyl Esters (FAEEs) Using Engineered Cyanobacteria

Area of Science:

• Synthetic Biology
• Metabolic Engineering
• Biotechnology

Background:

• Cyanobacteria are promising platforms for sustainable chemical production from CO2.
• Fatty acid-derived chemicals are vital for food and chemical industries.
• Current methods for producing these chemicals often rely on non-renewable resources.

Purpose of the Study:

• To engineer the model cyanobacterium Synechococcus elongatus PCC 7942 for the photosynthetic production of fatty acid ethyl esters (FAEEs) from CO2.
• To establish a novel metabolic pathway for FAEE synthesis in cyanobacteria.
• To optimize FAEE production yields.

Main Methods:

• Metabolic engineering of Synechococcus elongatus PCC 7942.
• Introduction of heterologous wax ester synthase (AftA) and ethanol production pathway.
• Incorporation of a heterologous phosphoketolase pathway to enhance acetyl-CoA supply.
• Optimization of culture conditions with a hexadecane overlay.

Main Results:

• Successfully engineered S. elongatus PCC 7942 to produce detectable levels of FAEEs from CO2.
• Enhanced FAEE production by introducing a phosphoketolase pathway.
• Achieved a photosynthetic FAEE production of 10.0 ± 0.7 mg/L/OD730.
• Demonstrated the first report of photosynthetic FAEE production from CO2 in cyanobacteria.

Conclusions:

• Metabolic engineering of cyanobacteria is a viable strategy for sustainable FAEE production.
• The engineered S. elongatus PCC 7942 strain represents a novel biological factory for producing FAEEs.
• This work opens new avenues for CO2 utilization in the chemical industry.