Red fluorescein detection method for nisin, and indicator bacterium and recombinant plasmid thereof

Abstract

The invention relates to a red fluorescein detection method for nisin, and an indicator bacterium and recombinant plasmid thereof. A recombinant plasmid vector is used for converting host Streptococcus lactis NZ9000 to obtain a gene engineering indicator bacterium strain which can respond to nisin to generate red fluorescein. The recombinant plasmid vector contains a red luciferase cobA gene controlled by an inducible strong promoter PnisA, and a chloramphenicol resistance gene. The gene engineering indicator bacterium TD304 constructed by the invention can be used for quickly detecting the content of nisin in a nisin fermentation liquid, thereby providing scientific parameters for establishing an optimal terminating point for fermenting production of nisin; and the gene engineering indicator bacterium TD304 can also be used for quickly detecting the content of nisin in water, food and milk beverages.

Description

technical field [0001] The invention belongs to the field of bioengineering and relates to the construction of bacterial strains, in particular to a nisin red fluorescein detection method, indicator bacteria and recombinant plasmids used. Background technique [0002] Nisin is nisin, a small molecular peptide produced by certain lactococcus, which has a good inhibitory effect on many Gram-positive bacteria that cause food spoilage, such as Clostridium, Bacillus, Listeria, Staphylococcus and other strains Function, and non-toxic to humans and animals, because nisin has a broad spectrum of antibacterial activity, it is widely used as a preservative in food, dairy and other industries. [0003] At present, the commonly used methods for detecting nisin are: plate diffusion method, enzyme-linked immunosorbent assay, bioluminescent detection method, etc. The disadvantage of the plate diffusion method is that there are many factors that affect the accuracy and sensitivity, and it t...

AI Technical Summary

Problems solved by technology

[0003] At present, the commonly used methods for detecting nisin are: plate diffusion method, enzyme-linked immunosorbent assay, bioluminescent detection method, etc. The disadvantage of the plate diffusion method is that there are many factors that affect the accuracy and sensitivity, and it takes a long time; Although the immunosorbent method is highly sensitive, it is prone to various cross-reactions; the bioluminescence detection method is fast, sensitive and specific, but the common luciferase reporter gene detection system and green fluorescent protein (GFP) reporter The system is interfered by the autofluorescence of cells, materials, etc., often resulting in low signal-to-noise ratio, and the luciferase reporter system needs to add exogenous substrates, and the detection method is cumbersome

Images