An engineering strain for highly expressing microcin J25 and its fermentation process

Abstract

The invention discloses an engineering strain for efficiently expressing Microcin-J25 and a fermentation process of the engineering strain. The engineering strain is constructed by structuring the McjA, McjB+McjC+McjD gene of the microcin J25 wild gene cluster into two plasmids, and transforming Escherichia coli MC41OO. The resultant engineering strain for efficiently expressing Microcin J25 is filed with the collection number CGMCC No. 12902. The engineering strain has the advantages that by modifying the MccJ25 wild gene cluster, the McjABCD genes are located in different plasmids and the engineering strain constructed by the transformed Escherichia coli MC4100 can efficiently express the MccJ25 and the laboratory 50L tank can reach 600mg / L, and 30T tank expression of industrial production reaches 500mg / L.

Description

technical field [0001] The invention relates to an engineering strain and a fermentation process for the engineering strain, in particular to an engineering strain for efficiently expressing Microcin J25 and a Microcin J25 fermentation process for the engineering strain, belonging to the technical fields of genetic engineering and fermentation optimization. Background technique [0002] Escherichia coli is prone to drug resistance, and the diseases caused by it have caused huge losses to livestock breeding, and it is urgent to solve this problem. [0003] Microcin J25 (MccJ25) is the abbreviation of colicin, and its expression bacteria is Escherichia coli. Mature MccJ25 is a lasso peptide consisting of 21 amino acids, in which the 1st to 8th amino acids at the N-terminal form a circular ring structure, and the 9th to 21st amino acids form a hairpin structure. The structure runs through the circular ring structure, and the tail is fixed by non-covalent interaction. Theoretic...

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Problems solved by technology

[0008] 2. The expression of MccJ25 is greatly affected by iron ions. Although the impact of iron ions can be alleviated by adding chelating agents, iron ions can be produced in all links of industrial production, which will eventually lead to the addition of chelating agents exceeding the standard and inhibit the growth of bacteria. Therefore, iron removal is not applicable in industrial production

[0009] 3. Modern pursuit of high-density fermentation, curve method to increase the expression of the target product, the expression of the MccJ25 wild gene cluster does not depend on the cell density, but strongly depends on the growth state of the bacteria, a large amount of expression in the late plateau stage, not suitable for high-density fermentation

[0010] 4. Industrial production pursues stability, high efficiency and low cost. The above-mentioned characteristics of the MccJ25 wild gene cluster can easily lead to fluctuations in production levels and increase production costs.

[0012] At present, the commercial expression system of Escherichia coli mainly involves the induced expression of single gene and single vector, and is not suitable for the coordinated expression of multiple genes and multiple vectors

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