US-20240218405-A1 - CORYNEBACTERIUM GLUTAMICUM VARIANT HAVING IMPROVED L-LYSINE PRODUCTION ABILITY, AND METHOD FOR PRODUCING L-LYSINE USING SAME

US20240218405A1US 20240218405 A1US20240218405 A1US 20240218405A1US-20240218405-A1

Abstract

Provided are a Corynebacterium glutamicum varient with improved L-lysine producing ability and a method of producing L-lysine using the same. The variant increases or enhances the expression of a gene encoding aspartate aminotransferase, thereby improving a production yield of L-lysine, as compared to a parent strain.

Inventors

LEE YOUNG JU
LEE SUN HEE
LEE HAN JIN
PARK SEOK HYUN
PARK JOON HYUN

Assignees

CJ CHEILJEDANG CORP

Dates

Publication Date: 20240704
Application Date: 20210525
Priority Date: 20210429

Claims (5)

1 . A Corynebacterium glutamicum variant with improved L-lysine producing ability by enhancing the activity of aspartate aminotransferase.
2 . The Corynebacterium glutamicum variant of claim 1 , wherein the enhancing of the activity of aspartate aminotransferase is inducing a site-specific mutation in a promoter of a gene encoding aspartate aminotransferase.
3 . The Corynebacterium glutamicum variant of claim 2 , wherein the gene encoding aspartate aminotransferase is represented by a nucleotide sequence of SEQ ID NO: 1.
4 . The Corynebacterium glutamicum variant of claim 1 , wherein the variant comprises any one of nucleotide sequences represented by SEQ ID NOS: 2 to 4.
5 . A method of producing L-lysine, the method comprising the steps of: a) culturing the variant of claim 1 in a medium; and b) recovering L-lysine from the variant or the medium in which the variant is cultured.

Description

TECHNICAL FIELD The present disclosure relates to a Corynebacterium glutamicum variant with improved L-lysine producing ability and a method of producing L-lysine using the same. BACKGROUND ART L-Lysine is an essential amino acid that is not synthesized in the human or animal body and must be supplied from the outside, and is generally produced through fermentation using microorganisms such as bacteria or yeast. In L-lysine production, naturally obtained wild-type strains or variants modified to have enhanced L-lysine producing ability thereof may be used. Recently, in order to improve the production efficiency of L-lysine, various recombinant strains or variants with excellent L-lysine producing ability and methods of producing L-lysine using the same have been developed by applying a genetic recombination technology to microorganisms such as Escherichia coli and Corynebacterium, etc., which are widely used in the production of L-amino acids and other useful substances. According to Korean Patent Nos. 10-0838038 and 10-2139806, nucleotide sequences of genes encoding proteins including enzymes related to L-lysine production or amino acid sequences thereof are modified to increase expression of the genes or to remove unnecessary genes and thereby improve the L-lysine producing ability. In addition, Korean Patent Publication No. 10-2020-0026881 discloses a method of replacing the existing promoter of a gene with a promoter with strong activity in order to increase expression of the gene encoding the enzyme involved in L-lysine production. As described, a variety of methods to increase the L-lysine producing ability are being developed. Nevertheless, since there are dozens of types of proteins such as enzymes, transcription factors, transport proteins, etc. which are directly or indirectly involved in the L-lysine production, it is necessary to conduct many studies on whether or not the L-lysine producing ability is increased according to changes in the activities of these proteins. PRIOR ART DOCUMENTS Patent Documents Korean Patent No. 10-0838038Korean Patent No. 10-2139806Korean Publication Patent No. 10-2020-0026881 DISCLOSURE Technical Problem An object of the present disclosure is to provide a Corynebacterium glutamicum variant with improved L-lysine producing ability. Further, another object of the present disclosure is to provide a method of producing L-lysine using the variant. Technical Solution The present inventors have studied to develop a novel variant with improved L-lysine producing ability using a Corynebacterium glutamicum strain, and as a result, they found that L-lysine production is increased by substituting a nucleotide sequence at a specific position in a promoter of aspB gene encoding aspartate aminotransferase, which is involved in the supply of a lysine precursor aspartate in the L-lysine biosynthetic pathway, thereby completing the present disclosure. An aspect of the present disclosure provides a Corynebacterium glutamicum variant with improved L-lysine producing ability by enhancing the activity of aspartate aminotransferase. As used herein, the term “aspartate aminotransferase (aspartate transaminase)” refers to an enzyme that catalyzes a conversion reaction of oxaloacetate to aspartate in the L-lysine biosynthetic pathway. According to a specific embodiment of the present disclosure, the aspartate aminotransferase may be derived from a strain of the genus Corynebacterium. Specifically, the strain of the genus Corynebacterium may be Corynebacterium glutamicum, Corynebacterium crudilactis, Corynebacterium deserti, Corynebacterium callunae, Corynebacterium suranareeae, Corynebacterium Corynebacterium lubricantis, Corynebacterium doosanense, efficiens, Corynebacterium uterequi, Corynebacterium stationis, Corynebacterium pacaense, Corynebacterium singulare, Corynebacterium humireducens, Corynebacterium marinum, Corynebacterium halotolerans, Corynebacterium spheniscorum, Corynebacterium freiburgense, Corynebacterium striatum, Corynebacterium canis, Corynebacterium ammoniagenes, Corynebacterium renale, Corynebacterium pollutisoli, Corynebacterium imitans, Corynebacterium caspium, Corynebacterium testudinoris, Corynebacaterium pseudopelargi, or Corynebacterium flavescens, but is not limited thereto. As used herein, “enhancing the activity” means that expression levels of genes encoding proteins such as target enzymes, transcription factors, transport proteins, etc. are increased by newly introducing or enhancing the genes, as compared to those of a wild-type strain or a strain before modification. Such enhancement of the activity also includes the case where activity of the protein itself is increased through substitution, insertion, or deletion of the nucleotide encoding the gene, or a combination thereof, as compared to activity of the protein originally possessed by a microorganism, and the case where the overall enzyme activity in cells is higher than that of the wild-type strain or t