The invention relates to the development of appropriate cultivation conditions for a bacteria to grow anaerobically (fermentatively) on a glycerol substrate. The method requires culturing bacteria having a functional 1,2-propanediol pathway and a functional type II glycerol dehydrogenase-dihydroxyacetone kinase pathway in a culture medium containing high concentrations of glycerol, a neutral to mildly acidic pII, low levels of potassium and phosphate, and high levels of CO2, such that glycerol is thus converted into a desirable product, such as ethanol, hydrogen, formate, succinate, or 1,2-propanediol.