Lactococcus lactis and method for simultaneously producing nisin and pediocin by using lactococcus lactis

Abstract

The invention provides lactococcus lactis and a method for simultaneously producing nisin and pediocin by using the lactococcus lactis. The method comprises the following steps: carrying out secondary PCR amplification by using a joint overlap extension technology to obtain a hybrid gene segment N-pedA including a Nisin leader peptide sequence and a pediocin structure gene, cloning N-pedA to a vector plasmid, converting the Nisin with strain preservation number as CGMCC No.10613 to produce lactococcus lactis SZ325. The strain can be used for simultaneously producing Nisin and Pediocin; the detection result shows that the yield of each of the two bacteriocins reaches over 95% of the original control strain. According to the lactococcus lactis, a novel method is provided for coexpression of Nisin and Pediocin; the production efficiency of the strain is improved; Nisin and Pediocin supplement each other; the antibacterial spectrum is expanded.

Description

technical field [0001] The invention relates to the field of biotechnology, in particular to a lactococcus lactis and a method for simultaneously producing nisin and lactin by using the same. Background technique [0002] Bacteriocin is a protein antibacterial substance produced by some bacteria. As a food preservative, it has the advantages of high efficiency, non-toxicity, acid resistance, high temperature resistance, no residue, and no drug resistance. Among them, the bacteriocins isolated from lactic acid bacteria mainly include Nisin and Pediocin, which have attracted widespread attention due to their strong activity against food-borne pathogens and spoilage bacteria. [0003] Nisin is a polypeptide substance containing 34 amino acids produced by certain Lactococcus lactis, which has a strong inhibitory effect on many Gram-positive bacteria including Staphylococcus, Streptococcus, and Bacillus. Nisin has heat stability, acid resistance, low temperature storage resistan...

AI Technical Summary

Problems solved by technology

[0005] Lactococcus lactis is a food-grade microorganism without endotoxin, which can be cultured on an industrial scale in cheap media by modern fermentation techniques. In addition, Lactococcus lactis has the ability to secrete proteins, so that many homologous proteins can be expressed on the surface or It is a good host bacteria for the expression of bacteriocin, but when Lactococcus lactis expresses Pediocin heterologously, the secretion system cannot effectively recognize the original leader peptide sequence of Pediocin, resulting in the inability to effectively secrete the Pediocin precursor out of the cell to obtain Active Pediocin

There is no report of Lactococcus lactis producing Nisin and Pediocin at the same time