Mixotrophic fermentation method performed to make one or more bioproducts such as alcohols, organic acids of less than 7 carbons, acetone, 2,3-butanediol and mixtures thereof with a microorganism. The mixotrophic fermentation method includes providing an isolated organism and providing a first feedstock and a second feedstock for use in a fermentation medium. The first feedstock includes 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 the second feedstock includes CO, CO2, carbonate, bicarbonate, H2, glycerol, methanol, formate, urea or mixtures thereof. The mixotrophic fermentation method also includes culturing the organism in the fermentation medium, whereby both feedstocks are metabolized and a fermentation broth is formed, the broth having at least one bioproduct. Optionally, the bioproduct may be separated from the broth.