Isolation?Structure Identification And Preliminary Studies On Antimicrobial Mechanism Of Bacillus Amyloliquefaciens BW-13 Antifungal Substance

Bacillus amyloliquefaciens is a capable microorganism with strong stress resistance,easy to culture,and be able to produce a series of substances with a wide range of antimicrobial activity.It has been developed as a new biological pesticide and is an important resourceful microorganism.We take a series of approaches to isolate its main components and successfully obtain the main components of the active substances DM-1 and DM-2,after physical and chemical properties and biological activity identification prove that they are ring(R-proline-glycine)and phenylalanine respectively.30L scale fermentation is performed to obtain the fermentation broth.Antifungal substance D2 component was stabilized at 80 ?for 3h;The antimicrobial substances was stabilized under pH2 to pH8 conditions for3h;Active substance by ninhydrin test,biuret experiments prove that fermentation broth are peptide or amino acid substances;Dialysis proves the molecular weight of antibacterial substances D2 component is less than 200.The DM-1 was separated by AB-8 macroporous resin,RP-18 column chromatography and gel exclusion chromatography HW-40 c.The substance is identified as a ring structure(R-proline-glycine).The DM-2 component is isolated by acid precipitation,followed by decolorization using adsorption resin S-8 macroporous,then by HZ-011 and D293 ion exchange resin treatment and obtained by RP-18 column chromatography.Its structure is identified as phenylalanine.By measuring the tolerance of wild-type Saccharomyces cerevisiae WHU2 a,chs1 and chs2 gene-deficient yeast CHT003,chs1 and chs3gene-deficient yeast CHT020,glucan synthase gene-deficient yeast ?fks1 found that D2 component have specific inhibition against CHT003;The result of sorbitol rescue experiment indicates the D2 substance has the function of fungal cell wall inhibitor.CFW rescue experiments prove D2 component has chitin synthase inhibition;Further research the effect against yeast and Botrytis cinerea spores and hyphae,the substance has damaging effect on yeast cell wall,it also has significant inhibition effect against the germination of Botrytis cinerea spores.