Abstract: Provided is a method of producing a product by culturing a carboxydotrophic acetogenic bacterium with a disrupting mutation in a lactate dehydrogenase enzyme in the presence of a substrate comprising CO, CO2, and/or H2. Preferably, the disrupting mutation reduces or eliminates the expression or activity of the enzyme such that the bacterium produces a reduced amount of lactate or no lactate.

Abstract: Provided is a method of producing a product by culturing a carboxydotrophic acetogenic bacterium with a disrupting mutation in a lactate dehydrogenase enzyme in the presence of a substrate comprising CO, CO2, and/or H2. Preferably, the disrupting mutation reduces or eliminates the expression or activity of the enzyme such that the bacterium produces a reduced amount of lactate or no lactate.

Abstract: The invention provides a carboxydotrophic acetogenic bacterium comprising a disrupting mutation in a lactate biosynthesis pathway enzyme and a method of producing a product by culturing the bacterium in the presence of a substrate comprising carbon monoxide. Preferably, the lactate biosynthesis pathway enzyme is lactate dehydrogenase (LDH) or another enzyme that converts pyruvate to lactate, wherein the disrupting mutation reduces or eliminates the expression or activity of the enzyme such that the bacterium produces a reduced amount of lactate or no lactate.