Research On Screening Of Bacillus Subtilis Degrading Aflatoxin B₁ And Its Function Study

Aflatoxin?Aflatoxin,AFT?is a secondary metabolite produced by aspergillus flavus and aspergillus parasiticus and other fungi,which have very strong carcinogenicity,teratogenicity and mutagenicity.It can not only do great harm to the health of human beings and animals,but also will be a significant impact on the economy at the same time.This study was to screen the strain which can degrade AFB₁,and optimized the fermentation conditions of bacterial strain,and then analysis the degradating effect by combining K-3 and K-TM.The details were described as follows:?1?The research on screening for strain which can degrade AFB₁;In the experiment,we used coumarin as the sole carbon and energy sources to preliminary screen the objective strain,finally we get 18 bacterium which can grow well in the coumarin plant in total.Among the 18 strains:3 strains from the soil,3 strains from yogurt,2 strains from animal waste,3 strains of probiotic products and 7 strains derived from laboratory strains.Then we used the rate of degradation rate as the index to screen again,and got two strains which can degrade the AFB₁ well,We put it as number K-3,K-3,and the rates of degradation are 83.87%,80.25%.?2?Bacterial taxonomic identification of objective strain K-3,K-TM: With the morphological features,physiological and biochemical test and 16 S r RNA sequences analysis of objective strain K-3,K-TM,they were eventually identified as Bacillus Subtitles.?3?The optimized condition on how objective strain K-3,K-TM to degrade aflatoxin B₁.The obtained best fermentation condition is described below:?K-3?amount of load 50 m L/250 m L,optimum temperature 37?,amount of inoculation 4%,original pH 7.0,and 150r/min for 48 h,degradation rate reached the peak of 88.07%?P<0.05?.?K-TM?amount of load 50 m L/250 m L,optimum temperature 37?,amount of inoculation 6%,original pH 7.0,and 150r/min for 60 h,degradation rate reached the peak of 84.81%?P<0.05?.Incubate K-3 and K-TM under the best fermentation condition.The optimal proportion of strain K-3 and strain K-3 was 1:2 for degrading aflatoxin B₁,and the maximum AFB₁ degradation rate was 88.43%.We provide a preliminary study for the future application of probiotics in the biological degradation of AFT.