The present application relates to the technical field of biocatalysis and biosynthesis, and specifically discloses a blue pigment and a biosynthesis method thereof. In the present application, an indigoidine synthetase and a 4-phosphopantetheinyl transferase are expressed by a metabolically engineered strain to catalyze the biosynthesis of the blue pigment N-acetyl-indigoidine from glutamine and N-acetylglutamine, and a molecular structure of the blue pigment is inferred by mass spectrometry, nuclear magnetic resonance spectroscopy, etc. The present application achieves the catalytic synthesis of N-acetyl-indigoidine from glutamine and N-acetylglutamine in Escherichia coli (E. coli), Corynebacterium glutamicum (C. glutamicum), Saccharomyces cerevisiae (S. cerevisiae), and Streptomyces. Compared with indigoidine, N-acetyl-indigoidine has a maximum absorption wavelength of 584 nm, and a stable color having high brightness that is not easy to fade. Thus, the blue pigment shows an extensive application range and a promising industrial production prospect.

The invention provides an Escherichia coli for synthesizing L-valine, a construction method and use thereof. The Escherichia coli of the invention is designated as Escherichia coli W3110 and was deposited in China Center for Type Culture Collection (Address: Bayi Road, Wuchang District, Wuhan City, Hubei Province) under the Accession No. CCTCC M 2022293 on Mar. 18, 2022. The recombinant Escherichia coli takes Escherichia coli as a starting strain, and a transcription regulation factor is overexpressed to obtain a recombinant Escherichia coli. The recombinant Escherichia coli for synthesizing L-valine of the invention is fermented in a 5 L fermentor with trace dissolved oxygen to test strains, the yield of L-valine reaches 112 g/L, and the OD of the bacterium is 104.

Ergothioneine-producing engineered bacteria and a construction method and use thereof are provided. The construction method includes: integrating a constitutive promoter PrrnD and an ergothioneine-synthesizing gene cluster egtABCDE derived from Mycolicibacterium neoaurum into a genome of Escherichia coli as a starting strain; and further mutating glutamate at a position 271 in an ATP phosphoribosyltransferase (HisG) gene of a strain produced above into lysine to produce the ergothioneine-producing engineered bacteria. With glucose as a main raw material, a fermentation culture can be conducted with the engineered bacteria to produce ergothioneine. The fermentation with the engineered bacteria to synthesize ergothioneine has advantages such as simple process and high production efficiency, can avoid the use of organic solvents and antibiotics in large quantities, and is suitable for industrial production.

The present invention provides a method for efficiently producing L-homophenylalanine and a strain producing L-homophenylalanine. In the present invention, a new route for the synthesis of L-homophenylalanine by a cascade enzymatic method using cheap benzaldehyde and pyruvic acid as raw materials is designed. By constructing the pathway-related enzymes into the same E. coli strain, a recombinant E. coli is obtained, with which L-homophenylalanine is catalytically produced through reaction in a 5 L reactor, with a yield of 100.9 g/L, a conversion rate of 94%, and ee>99%. Compared with the existing main methods for producing L-HPA, the production cost of L-homophenylalanine is greatly reduced. Thus, the present invention has good application prospects.

Disclosed are gene engineering bacteria for producing L-arginine and a construction method and an application of the gene engineering bacteria. According to the method, genes encoding a carbamoyl phosphate synthetase and a gene encoding an L-arginine biosynthesis pathway enzyme are integrated into Escherichia coli; the present invention has analyzed and reconstructed the arginine synthetic pathway and the metabolic flow related to arginine in the entire amino acid metabolic network in E. coli and finally obtained a genetically engineered bacterial strain which has a clear genetic background, carries no plasmids, undergoes no mutagenesis and is capable of stably and efficiently producing L-arginine.

An object of the present invention is to provide a method for producing a fucose-containing carbohydrate more efficiently as compared with that in related art. The present invention relates to any one protein of [1] a protein consisting of the amino acid sequence represented by SEQ ID NO: 2 or 4, [2] a mutant protein having an 1,3-fucosyltransferase activity and consisting of an amino acid sequence in which 1 to 20 amino acids are deleted, substituted, inserted, or added in the amino acid sequence represented by SEQ ID NO: 2 or 4, and [3] a homologous protein having an 1,3-fucosyltransferase activity and consisting of an amino acid sequence having an identity of 90% or more with the amino acid sequence represented by SEQ ID NO: 2 or 4.

The present disclosure relates to a genetically modified microorganism satisfying some of predetermined conditions. The predetermined conditions include: (I) succinate dehydrogenase activity or fumarate reductase activity being reduced or inactivated relative to a wild-type microorganism; (II) lactate dehydrogenase activity being reduced or inactivated relative to the wild-type microorganism; (III) the genetically modified microorganism having modified phosphoenolpyruvate carboxylase activity showing resistance to feedback inhibition by aspartic acid in wild-type phosphoenolpyruvate carboxylase activity, or exogenous phosphoenolpyruvate carboxylase activity having higher resistance to feedback inhibition by aspartic acid than that of the wild-type phosphoenolpyruvate carboxylase activity shown by the wild-type microorganism; and (IV) pyruvate:quinone oxidoreductase being reduced or inactivated relative to the wild-type microorganism.