A genetically engineered microorganism is provided. The genetically engineered microorganism has a higher expression level of acid-tolerant gene than a source microorganism. The acid-tolerant gene includes at least one of dsdA, dcuC and glaA. A method of preparing the genetically engineered microorganism and a method of producing a target chemical using the genetically engineered microorganism are also provided.

Disclosed are methods, compositions, systems, and protein compounds for the directed evolution of enzymes and proteins. The method comprising generating variant protein with a desired functionality, comprising one or more DNA expression templates comprising nucleic acid sequences encoding a variant protein, expressing the variant protein using cell-free protein synthesis; and analyzing one or more parameters associated with the variant protein.

Disclosed herein are methods for producing tulipalin A (-methylene--butyrolactone), recombinant cells or organisms for producing tulipalin A, enzymes needed for producing tulipalin A, and nucleic acids for expression of those enzymes.

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 disclosure relates, in part, to microbial hosts capable of synthesizing cis-3-hexenol, cis-3-hexenal, trans-3-hexenol, trans-3-hexenal, trans-2-hexenal, cis-2-hexenal and related compounds from hexanoic acid and methods for the preparation of cis-3-hexenol, cis-3-hexenal, trans-3-hexenol, trans-3-hexenal, trans-2-hexenal, cis-2-hexenal and related compounds.

The present invention relates to a cell capable of producing a fluorinated compound, in particular F-acetaldehyde and optionally F-acetyl-CoA and F-acetate, methods for producing fluorinated compounds in a cell and expression systems thereof.

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+-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.

A genetically engineered microbe capable of producing isoprene from a carbon source and method related thereto include a first nucleic acid sequence encoding a first enzyme, wherein the first enzyme is configured to catalyze one or more steps of a conversion from the carbon source to acetyl coenzyme A (A-CoA), a second nucleic acid sequence encoding a second enzyme of a mevalonate (MVA) pathway, and a heterologous nucleic acid sequence encoding a third enzyme, wherein the third enzyme is configured to catalyzing an isoprene-producing chemical reaction.