Screening Of Lactobacillus Against Fusarium Verticillium And Study On Its Antibacterial Properties

As one of the three main staples,corn has the reputation of "golden crop" and "longevity food".In 2019,China's corn production reached 26.77 million tons,ranking second in the world.Corn is extremely susceptible to mold contamination during storage.Therefore,the problem of mold prevention in corn is related to food and feed safety and national economic development.Fusarium verticillium,as the main pathogen of stem rot and ear rot in corn,directly affects the quality and safety of corn storage.Existing chemical antifungal agents are more damaging and easily harm the corn itself.Therefore,in the choice of antifungal agents,more and more attention is paid to safety and environmental protection.With the discovery of the functionality of lactic acid bacteria in recent years,the use of lactic acid bacteria to effectively inhibit mold is also one of the current research hotspots.Therefore,the application of lactic acid bacteria in corn to prevent mildew has a broad application prospect.In this study,132 strains of lactic acid bacteria stored in the laboratory were screened for bacteriostasis,and the bacteriostatic properties of the selected excellent strains were studied.In this study,Fusarium verticillium JF-5-1 was used as an indicator bacteria to carry out antibacterial experiments.The results showed that 17 strains of lactic acid bacteria showed good characteristics of inhibiting Fusarium verticillium,among which the 91 strain ZNJ160201 had the best antibacterial effect.The different antibacterial methods showed stable and excellent antibacterial effect.After further identification by 16 Sr DNA,strain 91 was Lactobacillus rhamnosus,and its MIC against Fusarium verticillium JF-5-1 was 8 mg/m L.It was found by SEM that the fermentation supernatant of strain 91 would break the mycelium of Fusarium verticillium JF-5-1 and the surface was rough and concave.Through the investigation of antibacterial activ e substances,it is found that the main antibacterial substances are organic acids.Through analysis and speculation,the antibacterial substances mainly include p-coumaric acid,p-hydroxybenzoic acid,azelaic acid,p-hydroxybenzoic aldehyde,citric acid,benzoic acid,2-(4-hydroxy-3,6-dioxo-hexa(Hydropyridazin-4-yl)acetic acid,phenyllactic acid,maleic acid,palmitic acid,2-amino-3-methoxy-benzoic acid,cetyl diacid,malonic acid,hydroxyisocaproic acid,erucic acid and phenylacetic acid,etc.,the specific antibacterial ability of each substance needs to be further verified.Studies have shown that the addition of No.91 strain 48 h fermentation supernatant can inhibit the growth of mold in corn and prolong the storage period of corn.The antibacterial potential of the fermentation supernatant of strain 91 in corn antifungal was verified,which provided theoretical support for the research and development of green antifungal agent.