The unique metabolism of acetogens has significant applications in biotechnology. In carbohydrate fermentations, the decarboxylation reactions end up in the conversion of organic carbon into carbon dioxide, the main greenhouse gas. This release is no longer compatible with the need to minimize the world CO emissions. It is not only an environmental concern but also not economically profitable in the frame of the biofuel competition with fossil fuels. Acetogens can ferment glucose without CO emission and convert one glucose molecule into three molecules of acetic acid, increasing the production yield of this latter by 50%. Acetogenesis does not replace glycolysis with a different pathway, but rather captures the CO from glycolysis and uses it for acetogenesis. Although three molecules of acetic acid can be produced in this way, the production of three molecules of ethanol would require an additional reducing agent such as hydrogen gas.