Process for controlling organic acid ratios in a carbon dioxide bioconversion process

A process comprising:

• providing a gaseous substrate comprising CO2 to a bioreactor;
• providing acetogenic bacteria and medium to the bioreactor to provide a fermentation broth;
• providing sodium ions to the bioreactor through one or more sodium ion sources;
• maintaining a pH of 6 or less in the fermentation broth;
• and
• fermenting the gaseous substrate with the acetogenic bacteria in the fermentation broth to produce one or more organic acids;
• wherein maintaining a pH of 6 or less in the fermentation broth provides a ratio of butyric acid to acetic acid concentration of 0.2 or more,
• wherein the acetogenic bacteria includes a sodium translocating ATPase that is active during fermentation in the bioreactor, and
• wherein the sodium ions are provided so that Na+ is maintained between 1000 to 11000 ppm (g/g) in culture broth.

A process comprising:

• providing a gaseous substrate comprising CO2 to a bioreactor;
• providing acetogenic bacteria and medium to the bioreactor to provide a fermentation broth;
• providing sodium ions to the bioreactor through one or more sodium ion sources;
• maintaining a pH of 6 or less in the fermentation broth;
• and
• fermenting the gaseous substrate with the acetogenic bacteria in the fermentation broth to produce one or more organic acids containing 3 or more carbon atoms;
• wherein the acetogenic bacteria includes a sodium translocating ATPase that is active during fermentation in the bioreactor, and
• wherein the sodium ions are provided so that Na+ is maintained between 1000 to 11000 ppm (g/g) in culture broth.