Recombinant microorganisms, plants, and plant cells are disclosed that have been engineered to express a mutant AROM polypeptide and/or mutant catechol-O-methyltransferase polypeptide alone or in combination with one or more vanillin biosynthetic enzymes or UDP-glycosyltransferases (UGTs). Such microorganisms, plants, or plant cells can produce vanillin or vanillin beta-D-glucoside.

Recombinant microorganisms, plants, and plant cells are disclosed that have been engineered to express a mutant AROM polypeptide and/or mutant catechol-O-methyltransferase polypeptide alone or in combination with one or more vanillin biosynthetic enzymes or UDP-glycosyltransferases (UGTs). Such microorganisms, plants, or plant cells can produce vanillin or vanillin beta-D-glucoside.

Provided are a method for producing an aromatic compound or a salt thereof using a transformed cell capable of producing the aromatic compound or the salt thereof, and this transformed cell. The present invention provides a method for producing an aromatic compound or a salt thereof, comprising the step of culturing a transformed cell with enhanced expression of a multi-pass transmembrane polypeptide represented by the following (A) or (B): (A) a polypeptide consisting of the amino acid sequence represented by SEQ ID NO: 2, and (B) a polypeptide consisting of an amino acid sequence having at least 76% identity to the amino acid sequence represented by SEQ ID NO: 2.

The invention pertains to a method for preparing cells that can be used as biocatalysts by inducing in them a growth-decoupled state, in which interferase inhibits the expression of genes except the ones that code for the pathway enzymes of interest. mRNAs that code for interferase-resistant products are overexpressed in the background of a metabolically-frozen cell. Enzymes that compete for a substrate or product of the pathway of interest may be altered such that the enzyme is sensitive to a site-specific protease, which protease is inducible in the host cell.

Disclosed herein are improved methods for production of 2-phenylethanol by microbial fermentation of substrates comprising carbon monoxide and/or carbon dioxide and further disclosed are genetically modified microorganisms for use in such methods that alleviate dependence on natural and petrochemical processes.

The invention pertains to a method for preparing cells that can be used as biocatalysts by inducing in them a growth-decoupled state, in which interferase inhibits the expression of genes except the ones that code for the pathway enzymes of interest. mRNAs that code for interferase-resistant products are overexpressed in the background of a metabolically-frozen cell. Enzymes that compete for a substrate or product of the pathway of interest may be altered such that the enzyme is sensitive to a site-specific protease, which protease is inducible in the host cell.