Continuous two stage, dual path anaerobic fermentation of butanol and other organic solvents using two different strains of bacteria

Abstract

The instant invention describes a process for the manufacture of butanol and like volatile organic compounds by fermenting carbohydrates, mainly polysaccharide, with micro-organisms which convert carbohydrates into mainly butyric acid and other acids. The acids are subsequently transferred to the solventogenesis production stage using a different strain of bacteria which continuously produces butanol and like volatile organic compounds, via a multistage fermentation process that is stable, high yielding (weight product per unit weight carbohydrates) and productive (faster throughput). By employing one microbe (the first) in the major pathway to produce the acid of choice specifically and faster, and provide for another microbe (the second) with the unique property to convert the acid to a solvent, carbohydrates are not wasted on ancillary product. The unique advantage of the second microbe is that it has the capability of converting acids into solvents (solventogenesis). For example Clostridium acetobutylicum passes though two morphologies, first acid producing (acidogenesis), yielding acetic, butyric, and lactic acids from the carbohydrate source. Then C. acetobutylicum shifts its physiology into a solventogenesis phase for the latter part of its life cycle, converting the acids it produced through acidogenesis into acetone, butanol, ethanol and isopropanol. The instant invention increases the yield by decreasing the production of ancillary acids and alcohols. It increases the volumetric productivity since the first bacteria produces butyric or a like acid faster and in a better yield than the second bacteria.

Dependencies are inferred from the claim text.