Isolation and identification of aflatoxin B1-degrading strains,optimization of fermentation conditions and analysis of active components
In order to screen a strain that can efficiently degrade aflatoxin B,(AFB,),soil was selected as the source of screening bacteria for enrichment culture.After preliminary screening with coumarin as the only carbon source and rescreening with AFB1 added,and 16S rDNA identification was performed on the selected strains,and their sequencing results were compared.The strain with the highest degradation rate of AFB1 was selected,the effects of fermentation time,fermentation temperature,initial pH,inoculation amount,and medium on the degradation rate of AFB1 were studied,the fermentation conditions were optimized by orthogonal experiment,and the degradation method was preliminarily explored.The results showed that 7 strains capable of degrading AFB1 were screened by preliminary screening and rescreening,which were indentified as Burkholderia sp.,and Burkholderia sp.D6 had the highest degradation rate of AFB1.The optimal fermentation conditions were obtained as follows:LB fermentation medium,fermentation time 84 h,fermentation temperature 37 ℃,initial pH 7.0,inoculation amount 10％.Under these conditions,the degradation rate of AFB,was(87.91±2.32)％.It was preliminarily judged that the active substance for degrading AFB,was protein or enzyme.In conclusion,a strain capable of efficiently degrading AFB,is screened,and protein or enzyme are involved in the degradation of AFB1.
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