Study On The Stability Of Bacillus Mojavensis Strain W-1 Against A.flavus Active Substances

Aspergillus flavus has a strong ability to infect,especially to peanut,corn and soybean etc.,which has large strength and wide range of pollution.The crops are contaminated by aspergillus flavus in the growing period,storage period,storage period and the processing into food products.The strong toxicity,the strong carcinogenicity and the high intensity,the wide range of pollution,make the research on the prevention and treatment of aspergillus Niger more and more urgent.In the ongoing study of the past,it was discovered that using biosafety measures to prevent the effects of a pest or harmful bacteria is a way to be environmentally effective and potentially..Bacillus mojavensis strainW-1 was a strain in the laboratory which was isolated from a soil contaminated by aspergillus flavus,and which was capable of producing active substances that inhibited aspergillus flavus.This topic mainly studied the inhibition of aflatoxin active substances produced by Bacillus mojavensis strain W-1.The main research thinking and results were:(1)The situation of Aspergillus flavus in the farmland of Qufu's suburbs was investigated and it was found that the number of aspergillus flavus in summer conditions was the largest,followed by spring and autumn,and the winter minimum,in addition,the peanut-growing soil contains more A.flavus than the corn-growing soil.However,in different seasons,although there are differences in different soils,it can be confirmed after comparing the data that the amount of Aspergillus flavus in farmland soil is indeed large,in other words,Aspergillus flavus contaminated farmland seriously.(2)The incubation time of the antibacterial activity-producing substance of Bacillus mojavensis strain W-1 with the strongest antibacterial activity was determined,and the stability of the antibacterial active substance produced by Bacillus mojavensis strain W-1 was tested.Stability experiments,pH stability experiments,UV stability experiments,light stability experiments,and genetic stability experiments are five properties of the experiment.Thermal stability experiments,pH stability experiments,UV stability experiments,light stability experiments,and genetic stability experiments.It was found that Bacillus mojavensis strain W-1produced a bacteriostatic active substance with a fermentation time of 48 hours.The antibacterial active substances produced by Bacillus mojavensis strain W-1 were not sensitive to temperature,and the results from 28�C to 121�C showed that high temperature had no effect on the activity of this substance which Bacillus mojavensis strain W-1 produces antibacterial active substances;antibacterial activity of Bacillus mojavensis strain W-1 can maintain high antibacterial activity in both strong and weak acid and alkali environments;UV-stabilization experiments showed that UV radiation of different durations and different doses had almost no effect on the antibacterial activity of antibacterial substances produced by Bacillus mojavensis strain W-1.The results of the light irradiation experiment showed that light did not affect the antibacterial active substances produced by Bacillus mojavensis strain W-1.That is to say,antibacterial activity of Bacillus mojavensis strain W-1 produced antibacterial activity under different light durations.They are maintained at a high level.The heritability of antibacterial substances produced by Bacillus mojavensis strain W-1 is very stable.After eight consecutive passages,their antibacterial activity has not changed.Based on these properties,it can be inferred that the bacteriostatic active substance produced by Bacillus mojavensis strain W-1 is a fatty substance.(3)In laboratory conditions,the minimum inhibitory concentration of Bacillus mojavensis strain W-1 was determined to inhibit the inhibition of aspergillus flavus by 125 ?g/mL.Then,We've been looking at Bacillus mojavensis strain W-1,which was the anti-bacterial activity of the peanut,the corn and the corn that were susceptible to the infection of the corn and the fungus.It was confirmed that the W-1 produced anti-bacterial activity that had a protective effect on the crops that had been affected by the yellow fungus by aspergillus flavus.(4)The molecular level of antibacterial active substance was preliminarily analyzed.Used PCR amplified technology,the encoding genes of antibacterial active substances were amplified.after the analysis of agarose gel electrophoresis,in the genetic database,Bacillus mojavensis strain W-1 was compared with three genes encoding antibacterial active substances.The genes for antibacterial active substances were: albF,bacD and sfP.The antibacterial active substances encoded by these three genes were: bacilysin,surfactin and subtilosin.All three substances have antibacterial and bacteriolytic effect.This preliminary determination of the active ingredients of aflatoxin in Bacillus mojavensis strain W-1 producing antibacterial active substances from the gene level,and also confirms that Bacillus mojavensis strain W-1 has antibacterial activity.