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: One or more genes in a biosynthesis pathway for a vitamin or other essential nutrient which is needed for the survival of a microorganism can be used as an effective selective marker to identify cells transformed with an exogenous nucleic acid. The microorganism does not naturally contain or express the one or more gene. This permits genetic manipulations to be performed. It permits lower cost fermentations to be performed. It permits production of the essential nutrient for subsequent commodity use.

Abstract: One or more genes in a biosynthesis pathway for a vitamin or other essential nutrient which is needed for the survival of a microorganism can be used as an effective selective marker to identify cells transformed with an exogenous nucleic acid. The microorganism does not naturally contain or express the one or more gene. This permits genetic manipulations to be performed. It permits lower cost fermentations to be performed. It permits production of the essential nutrient for subsequent commodity use.

Abstract: The invention provides a bacterium with an increased tolerance to butyric acids, such as 2-hydroxybutyric acid (2-HIBA). In particular, the invention provides a bacterium that tolerates at least 2.5 g/L of butyric acid. The bacterium may be derived, for example, from genus Clostridium, Moorella, Oxobacter, Peptostreptococcus, Acetobacterium, Eubacterium, or Butyribacterium.

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.

Abstract: The invention provides a recombinant, acetogenic, carboxydotrophic bacterium that lacks secondary alcohol dehydrogenase or comprises an inactivated secondary alcohol dehydrogenase. The inactivated secondary alcohol dehydrogenase may be encoded by a secondary alcohol dehydrogenase gene comprising an inactivating mutation that reduces the ability of the bacterium to convert acetone to isopropanol and to convert methyl ethyl ketone to 2-butanol. Since a bacterium that lacks secondary alcohol dehydrogenase or comprises an inactivated secondary alcohol dehydrogenase accumulates carbonyl-containing compounds, the invention also provides a method of producing carbonyl-containing compounds, such as acetone and methyl ethyl ketone.

Abstract: The invention relates to a process for optimizing the production of ethanol by microbial fermentation, particularly microbial fermentation of substrates comprising CO. The process involves monitoring the hydrogen production by the microorganism, determining an optimum hydrogen production and adjusting the substrate supply rate in response to a change in the hydrogen production thereby keeping the hydrogen production within a desired range.

Abstract: The present invention relates to methods for sustaining a microbial culture during periods of limited substrate supply. In accordance with the methods of the invention, a microbial culture comprising carboxydotrophic bacteria can be sustained during periods of limited substrate supply by maintaining the temperature of the microbial culture at a temperature below an optimum operating temperature. Examples of periods of limited substrate supply include when the microbial culture is transported to a remote location or during time when it is stored.

Abstract: The invention relates to a process for optimising the production of ethanol by microbial fermentation, particularly microbial fermentation of substrates comprising CO. The process involves monitoring the hydrogen production by the microorganism, determining an optimum hydrogen production and adjusting the substrate supply rate in response to a change in the hydrogen production thereby keeping the hydrogen production within a desired range.

Abstract: The invention relates to improvements in the production of alcohols by microbial fermentation, particularly to production of alcohols by microbial fermentation of a substrate comprising CO. It more particularly relates to the addition of an inorganic sulfur source to a fermentation system such that one or more micro-organisms convert a substrate comprising CO to alcohols. In a particular embodiment, a microbial culture is provided with sodium polysulfide, wherein a substrate comprising CO is converted to products including ethanol and 2,3-butanediol.

Abstract: The invention relates to the production of alcohols by microbial fermentation, particularly to production of alcohols by microbial fermentation of substrates comprising CO. It more particularly relates to processes for the production of alcohols from their corresponding acids in the presence of a substrate comprising CO. In particular embodiments, a fermentation reaction producing acid(s) and optionally alcohol(s) is perturbed such that at least a portion one or more of acid(s) is converted to alcohol.

Abstract: The invention relates to improvements in the production of alcohols by microbial fermentation, particularly to production of alcohols by microbial fermentation of a substrate comprising CO. It more particularly relates to the provision of an inorganic organic sulfur source to a fermentation system such that one or more micro-organisms convert a substrate comprising CO to alcohols. In a particular embodiment, a microbial culture is provided with sodium polysulfide, wherein a substrate comprising CO is converted to products including ethanol and 2,3-butanediol.

Abstract: The present invention relates to methods for sustaining a microbial culture during periods of limited substrate supply. In accordance with the methods of the invention a microbial culture comprising carboxydotrophic bacteria can be sustained during periods of limited substrate supply by maintaining the temperature of the microbial culture at a temperature below an optimum operating temperature.

Abstract: The invention relates to the production of products such as alcohols and acids by microbial fermentation, particularly microbial fermentation of substrates comprising CO. It more particularly relates to methods and systems for improving efficiency of production products by microbial fermentation. In particular embodiments, the invention provides a method of controlling substrate supply, such that production of desired metabolites is optimised.

Abstract: The invention relates to the production of alcohols by microbial fermentation, particularly to production of alcohols by microbial fermentation of substrates comprising CO. It more particularly relates to processes for the production of alcohols from their corresponding acids in the presence of a substrate comprising CO. In particular embodiments, a fermentation reaction producing acid(s) and optionally alcohol(s) is perturbed such that at least a portion one or more of acid(s) is converted to alcohol.