The present invention discloses a RamA transcription factor mutant for promoting the production of N-acetylglucosamine and use thereof. The mutant is obtained by mutating lysine at position 90 to asparagine and serine at position 92 to lysine in a parent having an amino acid sequence as shown in SEQ ID NO: 2. The present invention provides a genetically engineered strain that overexpresses the RamA transcription factor mutant and increases the production of N-acetylglucosamine. By overexpressing the transcription factor RamA that is involved in the regulation of carbon metabolism, the extracellular accumulation of N-acetylglucosamine is increased, with a maximum concentration reaching 31.5 g/L, which lays a foundation for further metabolic engineering of Corynebacterium glutamicum to produce glucosamine. The method for constructing recombinant Corynebacterium glutamicum of the invention is simple, and convenient in use, and thus has good application prospects.

Arginine deiminase (ADI)-containing genetically engineered Corynebacterium glutamicum (C. glutamicum), a fusion protein cipA-arc, use thereof, and a method for preparing [.sup.14/15N]-L-citrulline through enzymatic catalysis are provided. The ADI-containing genetically engineered Corynebacterium glutamicum (C. glutamicum) has a deposit number of CGMCC No. 19404, which expresses a fusion protein cipA-arc. Both the genetically engineered strain and the fusion protein cipA-arc can be used to convert [.sup.14/15N]-L-arginine into [.sup.14/15N]-L-citrulline.

Described are methods for increasing the production of small molecules in a submerged Corynebacterium culture by supplementing Corynebacterium growth medium with the non-enzymatic fraction of spent Trichoderma fermentation broth.

The present disclosure relates to a Corynebacterium sp. mutant strain having increased L-arginine or L-citrulline productivity and a method of producing L-arginine or L-citrulline using the same. The Corynebacterium sp. mutant strain has enhanced activity of acetylornithine aminotransferase involved in the L-arginine biosynthesis pathway, and thus is capable of producing L-arginine or L-citrulline productivity in an increased yield compared to a parent strain.

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 present disclosure relates to a modified polypeptide with attenuated activity of citrate synthase, a microorganism producing leucine comprising the modified polypeptide, and a method for producing an L-amino acid using the microorganism.

The present disclosure relates to an isopropylmalate synthase variant and a method of producing L-leucine using the same.

The present disclosure relates to a Corynebacterium sp. mutant strain having increased L-arginine or L-citrulline productivity and a method of producing L-arginine or L-citrulline using the same. The Corynebacterium sp. mutant strain has enhanced activity of acetylglutamate kinase involved in the L-arginine biosynthesis pathway, and thus is capable of producing L-arginine or L-citrulline in an increased yield compared to a parent strain.