Described are compositions and methods relating to modified yeast that over-express MIG transcriptional regulator polypeptides. The yeast produces a deceased amount of acetate compared to parental cells. Such yeast is particularly useful for large-scale ethanol production from starch substrates where acetate in an undesirable end product.

Methods of microbial screening for identifying alcohol acyltransferases for ester biosynthesis and submodules for ester pathways to produce butyryl-coenzyme A derived esters are disclosed. The method includes the introduction preselected plasmids into a respective host strain to form engineered microbes, in situ fermentation thereof followed by a colorimetric assay for quantification of production of the target ester. In situ fermentation includes inoculating each well of a microplate that have a culture media for producing target esters with one of the engineered microbes, adding an overlay of a solvent to each, and incubating the same. The colorimetric assay includes transfer of a quantity of the overlay from each well to respective clean wells of a new microplate, treatment of each well to form an iron-hydroxamic acid complex aqueous phase, centrifugation of the microplate, and measurement of the absorbance at 520 nm and comparison to a standard curve for the target ester.

The present disclosure is related to genetically engineered microbial strains and related bioprocesses for the production of products from acetyl-CoA. Specifically, the use of dynamically controlled synthetic metabolic valves to reduce the activity of certain enzymes, leads to increased product production in a two-stage process.

A modified microorganism containing a genetic modification that suppresses a transcription factor that controls expression of pyruvate dehydrogenase, in which the microorganism has and a production pathway of a C6 compound, and in which the C6 compound is at least one compound selected from the group consisting of adipic acid, hexamethylenediamine, 1,6-hexanediol, 6-aminohexanoic acid, 6-amino-1-hexanol, 6-hydroxyhexanoic acid, 3-oxoadipic acid, 3-hydroxyadipic acid, and 2,3-dehydroadipic acid.

A process for producing butanol is provided, involving: A) mixing water, lactate, an enzyme mixture comprising at least one enzyme, at least one cofactor and at least one coenzyme, to prepare a reaction mixture; B) catalytically reacting the reaction mixture for an amount of time sufficient to cause conversion of lactate into butanol; and wherein the conversion of lactate into butanol in B) is associated with a regeneration system of NAD (P).sup.+/NAD (P) H and/or acetyl-CoA/CoA.

A method of treating a biofilm on a surface, comprising: providing a surface having a biofilm; and administering to the surface a treatment that reduces a concentration of pyruvate of the biofilm, comprising pyruvate produced by at least a portion the biofilm, under conditions effective reducing maintenance of the biofilm on the surface. A composition, comprising purified enzyme, within a particle, effective for reducing pyruvate concentration in an aqueous suspension of the composition.

A combination of an electrochemical device for delivering reducing equivalents to a cell, and engineered metabolic pathways within the cell capable of utilizing the electrochemically provided reducing equivalents is disclosed. Such a combination allows the production of commodity chemicals by fermentation to proceed with increased carbon efficiency.

Modified bacterial strains are provided. The strains can generate a desired product such as pyruvate and products derived from pyruvate. Methods of generating pyruvate and products derived from pyruvate are also provided. The modified bacterial strains have at least one mutation in a gene coding for proteins in a pyruvate dehydrogenase complex such that the mutation allows a cell to accumulate pyruvate and/or products derived from pyruvate.

The present invention provides a dehydrogenase mutant L283V/L286V, and a preparation method and use thereof, and relates to the field of biomedicine technologies. An amino acid sequence of the mutant L283V/L286V is as shown in SEQ ID NO: 1; and the mutant is prepared by simultaneously mutating 283.sup.rd and 286.sup.th leucine of a dehydrogenase with an amino acid sequence as shown in SEQ ID NO: 3 into valine. The dehydrogenase mutant L283V/L286V shows high selectivity in catalyzing myosmine reduction reaction in a whole cell system to produce S-nornicotine, and has relatively high dehydrogenase and imine reductase activities, a short enzyme reduction time, and a high transformation rate. The product S-nornicotine obtained through the reaction has extremely high optical purity, which reduces the operation difficulty of subsequent purification.

Disclosed is a method of producing lactic acid using a recombinant acid-resistant yeast with inhibited lactate metabolism and alcohol production. More specifically, disclosed are a recombinant acid-resistant yeast in which lactate consumption reaction is reduced and which is imparted with lactic-acid-producing ability to thereby exhibit improved lactic-acid-producing ability and reduced ethanol production, and a method of producing lactic acid using the same.