Mixotrophic fermentation method for making acetone, isopropanol, butyric acid and other bioproducts, and mixtures thereof

A mixotrophic fermentation method comprising

• (i) providing an isolated naturally acetogenic organism;
• (ii) providing a fermentation medium comprising a first feedstock and a second feedstock wherein said first feedstock comprises a carbon source that is metabolized by the native form of the organism at a rate of less than 0.01 g/hr/g cell mass;
• and
• (iii) culturing said organism in said fermentation medium, whereby both feedstocks are metabolized and acetic acid is formed,
• wherein the amount of acetic acid produced per biomass unit weight is less than about 50% of that produced in autotrophic fermentation with the same organism under the same conditions.

A mixotrophic fermentation method comprising

• (i) providing an isolated naturally acetogenic organism that has been genetically modified;
• (ii) providing a fermentation medium comprising a first feedstock and a second feedstock wherein said first feedstock comprises a sugar that is metabolized by the native form of the organism at a rate of less than 0.01 g/hr/g cell mass;
• and
• wherein said second feedstock comprises CO, CO2, carbonate, bicarbonate, H2, glycerol, methanol, formate, urea or mixtures thereof;
• and
• (iii) culturing said organism in said fermentation medium, whereby both feedstocks are metabolized and a fermentation broth is formed, which broth comprises at least one bioproduct.