Clostridium Beijerinckii

This bacteria shows promise in the bioproduction? of butanol using a fibrous bed bioreactor.

Engineers at Ohio State University have found a way to double the production of butanol, which can be used as a biofuel in automobiles. The process improves on the conventional method for brewing butanol in a bacterial fermentation? tank.¹ Normally, bacteria only produce perhaps 15 grams of butanol for every liter of water in a bioreactor, before the tank becomes too toxic for the bacteria to survive.

Shang-Tian Yang, professor of chemical and biomolecular engineering at Ohio State and colleagues developed a mutant strain of the bacterium Clostridium beijerinckii in a fibrous bed bioreactor containing bundles of polyester fibers. In that environment, the mutant bacteria produced up to 30 grams of butanol per liter. The process was described in a presentation to the American Chemical Society, or ACS, in August 2009.²

Yang said that this use of the patented fibrous-bed bioreactor will save money. He says that the recovery? and purification? of butanol account for about 40% of the total production cost but that the mutant bacteria and bioreactor allows for the creation of butanol at higher concentrations. Yang says that he believes costs associated with recovery and purification can be further reduced making biofuel production more economical. Currently, a gallon of butanol costs approximately $3.00, similar to the current price for a gallon of gasoline.

Yang's team is applying for a patent on the mutant bacterium and the butanol production methodology, and will work with industry to develop the technology.

How the fibrous bed bioreactor works³

One use of the bioreactor has been in converting waste whey lactose into coproducts, something of interest to the dairy industry. A wide range of products can be obtained from whey? fermentation, including single cell protein, methane, alcohols such as ethanol and butanol, organic acids? such as lactic, acetic, propionic, and citric, vitamins, and biopolymer?s such as xanthan gum. However, production of a suitable fermentation product from whey must take into account technological, market, and economic factors. None of the existing whey fermentation processes have achieved wide-scale use in the dairy industry.

Most organic acids are presently produced via petrochemical? routes due to the poor reaction rate found in conventional fermentation methods. Some organic acids, such as lactic, acetic, and propionic acids, and their salts, however, may be produced economically from fermentation of sugars such as lactose?, glucose, fructose?, sucrose? and organic acids such as lactate? or pyruvate? present in culture media or biomass including whey?, corn, steep liquor? or sulfite liquor?.