Aspects of the disclosure relate to compositions of enzyme-binding polypeptides (EBPs) that modify the substrate specificity of an enzyme and a method for identifying an EBP that modifies substrate specificity of an enzyme binding at least one substrate, the method comprising: contacting the enzyme with a polypeptide library comprising a plurality of EBPs that bind different epitopes of the enzyme; identifying EBPs that bind to the enzyme to form an EBP-enzyme complex; assaying for the activity level and substrate specificity of the EBP-enzyme complex; and identifying EBPs that modify the substrate specificity of the enzyme by identifying EBPs that, when in an EBP-enzyme complex, have a different substrate specificity than un-complexed EBP; wherein the catalytic rate constant of the EBP-enzyme complex is ≥50% of the un-complexed enzyme for at least one substrate and/or wherein the EBP-enzyme complex retains binding to a substrate.

The present disclosure provides recombinant microorganisms and methods for the production of 4-HMF, 2,4-furandimethanol, furan-2,4-dicarbaldehyde, 4-(hydroxymethyl)furoic acid, 2-formylfuran-4-carboxylate, 4-formylfuran-2-carboxylate, and/or 2,4-FDCA from a carbon source. The method provides for engineered microorganisms that express endogenous and/or exogenous nucleic acid molecules that catalyze the conversion of a carbon source into 4-HMF, 2,4-furandimethanol, furan-2,4-dicarbaldehyde, 4-(hydroxymethyl)furoic acid, 2-formylfuran-4-carboxylate, 4-formylfuran-2-carboxylate, and/or 2,4-FDCA. The disclosure further provides methods of producing polymers derived from 4-HMF, 2,4-furandimethanol, furan-2,4-dicarbaldehyde, 4-(hydroxymethyl)furoic acid, 2-formylfuran-4-carboxylate, 4-formylfuran-2-carboxylate, and/or 2,4-FDCA.

Genetically modified microorganisms that have the ability to convert carbon substrates into multicarbon products. Methods of making these genetically modified microorganisms and methods of using them. Vectors encoding enzymes for use in converting carbon substrates into multicarbon products.

Described herein are non-natural NAD.sup.+-dependent alcohol dehydrogenases (ADHs) capable of at least two fold greater conversion of methanol or ethanol to formaldehyde or acetaldehyde, respectively, as compared to its unmodified counterpart. Nucleic acids encoding the non-natural alcohol dehydrogenases, as well as expression constructs including the nucleic acids, and engineered cells comprising the nucleic acids or expression constructs are described. Also described are engineered cells expressing a non-natural NAD.sup.+-dependent alcohol dehydrogenase, optionally include one or more additional metabolic pathway transgene(s), methanol metabolic pathway genes, target product pathway genes, cell culture compositions including the cells, methods for promoting production of the target product or intermediate thereof from the cells, compositions including the target product or intermediate, and products made from the target product or intermediate.

The invention describes a process for the production of ethanol from a composition comprising glucose and between 50 μM and 100 mM acetic acid, said process comprising fermenting said composition in the presence of a recombinant yeast which is capable to convert acetic acid anaerobically; maintaining the amount of undissociated acetic acid at a value of at least 50 μM; and recovering the ethanol. Said process is useful for both starch and cellulosic based, acetic acid containing hydrolysates and advantageously results in a greater consumption of acetic acid and thus higher ethanol yields.

Microorganisms are genetically engineered to produce 3-hydroxypropionate (3-HP). The microorganisms are carboxydotrophic acetogens. The microorganisms produce acetyl-coA using the Wood-Ljungdahl pathway for fixing CO/CO.sub.2. A β-alanine pyruvate aminotransferase from a microorganism that contains such an enzyme is introduced. Additionally, an acetyl-coA carboxylase may also be introduced. The production of 3-HP can be improved. This can be effected by improved promoters or higher copy number or enzymes that are catalytically more efficient.

In a method for producing acetoin, butanediol, or butanol from ethanol according to the present invention, a cell-free catalysis method was used by designing an artificial synthetic pathway so that proteins of NOX, EtDH, FLS, BDH, and DDH and variant proteins thereof exhibit cascade catalytic activity as enzymes. Compared to existing fermentation methods using microorganisms, the production method according to the present invention does not require cell growth and has a short synthetic pathway, a fast reaction rate, high yield and productivity, adjustment of targeted reaction conditions is convenient, and butanol may be effectively produced. Moreover, same may be reused numerous times by fixing the proteins to nano-particles, and are also effective for producing acetoin, butanediol, or butanol, thus being economical. Therefore, the production method may be usefully adopted in the relevant industries requiring acetoin, butanediol, or butanol.

The present invention relates to methods of providing a biomass residuum and compositions thereof. In particular examples, the biomass residuum includes one or more high value amino acids, even after removal of mixed alcohol components. In particular, the methods include implementing pre-treatment conditions and employing fermentation conditions including modified organisms.

The present invention relates to a yeast cell, in particular a recombinant yeast cell, the cell lacking enzymatic activity needed for the NADH-dependent glycerol synthesis or the cell having a reduced enzymatic activity with respect to the NADH-dependent glycerol synthesis compared to its corresponding wild-type yeast cell, the cell comprising one or more heterologous nucleic acid sequences encoding an NAD.sup.+-dependent acetylating acetaldehyde dehydrogenase (EC 1.2.1.10) activity. The invention further relates to the use of a cell according to the invention in the preparation of ethanol.

The present invention provides for a mechanism to reduce glycerol production and increase nitrogen utilization and ethanol production of recombinant microorganisms. One aspect of this invention relates to strains of S. cerevisiae with reduced glycerol productivity that get a kinetic benefit from higher nitrogen concentration without sacrificing ethanol yield. A second aspect of the invention relates to metabolic modifications resulting in altered transport and/or intracellular metabolism of nitrogen sources present in corn mash.