Acetogenesis

Acetogenesis is a process through which acetyl-CoA^[1] or acetic acid is produced by anaerobic bacteria through the reduction of CO₂ via the Wood–Ljungdahl pathway. Other microbial processes that produce acetic acid (like certain types of fermentation or the oxidative breakdown of carbohydrates or ethanol by acetic acid bacteria) are not considered acetogenesis. The diverse bacterial species capable of acetogenesis are collectively called acetogens.

Reduction of CO₂ to acetic acid via the Wood–Ljungdahl pathway requires an electron source (e.g., H₂, CO, formate, etc.).^[2] When acetogens are grown autotrophically, they synthesize acetic acid only through the Wood–Ljungdahl pathway; but when they are grown heterotrophically, they can produce additional acetic acid by oxidation of the carbon source (carbohydrates, organic acids, or alcohols).^[1] Once produced, acetyl-CoA can be incorporated into biomass or converted to acetic acid.^[1]