The present invention discloses a method for modifying an amino acid attenuator, a class of amino acid attenuator mutants, engineered bacteria created on the basis of the amino acid attenuator mutants, and use of the engineered bacteria. The present invention protects a method for relieving the attenuation regulation of an amino acid operon gene, which is modification of the amino acid operon gene by: removing a gene coding for a leader peptide and an anterior reverse complementary palindromic sequence in the terminator stem-loop structure, and maintaining a posterior reverse complementary palindromic sequence in the terminator. The amino acid operon particularly can be histidine operon, tryptophan operon, phenylalanine operon, alanine operon, threonine operon and etc. The present invention can be used for the production of amino acids and derivatives thereof in fermentation by bacteria, providing a novel method for improving the production of amino acids in fermentation.

The present invention discloses a method for modifying an amino acid attenuator, a class of amino acid attenuator mutants, engineered bacteria created on the basis of the amino acid attenuator mutants, and use of the engineered bacteria. The present invention protects a method for relieving the attenuation regulation of an amino acid operon gene, which is modification of the amino acid operon gene by: removing a gene coding for a leader peptide and an anterior reverse complementary palindromic sequence in the terminator stem-loop structure, and maintaining a posterior reverse complementary palindromic sequence in the terminator. The amino acid operon particularly can be histidine operon, tryptophan operon, phenylalanine operon, alanine operon, threonine operon and etc. The present invention can be used for the production of amino acids and derivatives thereof in fermentation by bacteria, providing a novel method for improving the production of amino acids in fermentation.

The present invention relates to genetically modified bacteria and methods of optimizing genetically modified bacteria for the production of a metabolite.

Provided are a cAMP receptor protein variant and coding sequence, a microorganism including the same, and a method of producing a L-amino acid using the same.

This invention relates to the bioproduction of substituted or unsubstituted phenylacetaldehyde, 2-phenylethanol, phenylacetic acid or phenylethylamine by subjecting a starting material comprising glucose, L-phenylalanine, substituted L-phenylalanine, styrene or substituted styrene to a plurality of enzyme catalyzed chemical transformations in a one-pot reaction system, using recombinant microbial cells overexpressing the enzymes. To produce phenylacetaldehyde from styrene, the cells are modified to overexpress styrene monooxygenase (SMO) and styrene oxide isomerase (SOI). To produce phenylacetic acid from styrene, SMO, SOI and aldehyde dehydrogenase are overexpressed. Alternatively, to produce 2-phenylethanol, SMO, SOI and aldehyde reductase or alcohol dehydrogenase are overexpressed, while to produce phenylethylamine, SMO, SOI and transaminase are overexpressed.

The present invention provides engineered tyrosine ammonia-lyase (TAL) polypeptides and compositions thereof. In some embodiments, the engineered TAL polypeptides have been optimized to provide enhanced catalytic activity while reducing sensitivity to proteolysis and increasing tolerance to acidic pH levels. The invention also provides methods for utilization of the compositions comprising the engineered TAL polypeptides for therapeutic and industrial purposes.

Provided is a group of new uridine diphosphate (UDP)-glycosyltransferases, which are carbon glycoside glycosyltransferases, wherein the glycosyltransferases can specifically and efficiently catalyze the carbon glycoside glucosylation of a dihydrochalcone(s) compound or a 2-hydroxyflavanone(s) compound, thereby producing a carbon glycoside dihydrochalcone(s) compound or a carbon glycoside-2-hydroxyflavanone(s) compound; and a flavonoid carbon glycoside(s) compound is formed from a carbon glycoside-2-hydroxyflavanone(s) compound by means of a further dehydration reaction. Further provided is the use of said new UDP glycosyltransferases in artificially constructed recombinant expression systems to produce a carbon glycoside dihydrochalcone(s) compound or a flavonoid carbon glycoside(s) compound by means of fermentation engineering.

Systems, methods, and host cells utilizing a PopQC construct for enhancing product biosynthesis by exploitation of non-genetic cell-to-cell variation are disclosed. The PopQC construct includes at least a product-responsive biosensor and a selection gene.

Systems, methods, and host cells utilizing a PopQC construct for enhancing product biosynthesis by exploitation of non-genetic cell-to-cell variation are disclosed. The PopQC construct includes at least a product-responsive biosensor and a selection gene.

Single-module nonribosomal peptide synthetases (NRPSs) and NRPS-like enzymes activate and transform carboxylic acids in both primary and secondary metabolism; and are of great interest due to their biocatalytic potentials. The single-module NRPS IvoA is essential for fungal pigment biosynthesis. As disclosed herein, we show that IvoA catalyzes ATP-dependent unidirectional stereoinversion of L-tryptophan to D-tryptophan with complete conversion. While the stereoinversion is catalyzed by the epimerization (E) domain, the terminal condensation (C) domain stereoselectively hydrolyzes D-tryptophanyl-S-phosphopantetheine thioester and thus represents a noncanonical C domain function. Using IvoA, we demonstrate a biocatalytic stereoinversion/deracemization route to access a variety of substituted D-tryptophan analogs in high enantiomeric excess.