Characterisation And Application Of Aflatoxin-degradating Paenibacillus Pabuli E1

Aflatoxin（AFT） is a group of toxic fungal metabolites with similar chemical structures.They have been found in many crops,such as corn,peanuts and their derivatives.Aflatoxin are extremely toxic to both humans and animals.Therefore,it is necessary to explore corresponding measures to remove aflatoxin from grains or grain-derived products.Compared with traditional physical and chemical methods,the removal of aflatoxin by biological methods has the characteristics of high removal rate,strong specificity,good probiotics and environmental friendliness.Therefore,the removal of aflatoxin by biological methods has become a research hotspot of researchers in recent years.In order to be able to find a detoxifier that can be used in actual biological methods to remove aflatoxin,this paper studied the conditions,degradation rate and practical application potential of Paenibacillus pabuli E1 to degrade aflatoxin.The main research contents of this paper are as follows:（1）To study the growth characteristics of Paenibacillus pabuli E1.Cultivating the Paenibacillus pabuli E1 for 24 hours with different inoculation amounts,different p H values,different liquid volume,and different temperature culture systems,after the cultivation is completed,using a spectrophotometer measures the optical density OD₆₀₀.Results:when the liquid volume is 2%,the p H value is 7 and the temperature is 27℃,the growth of Paenibacillus pabuli E1 is the best;（2）To study the best conditions for the aflatoxin degradation by Paenibacillus pabuli E1.The inoculum 2%,the p H 7 and the temperature 27°C cultivate for 24 hours to provide fermentation broth.To study the single factors with different effects:the effect of inoculum,p H value,temperature and culture time of the degradation system are influence on the aflatoxin degradation by Paenibacillus pabuli E1.The three factors that have the greatest impact on the degradation effect are selected on the basis of a single factor,and the response surface methodology sub-category Box-Behnken is used to design the central combination experiment to optimize the experimental plan,which is to optimize the influencing conditions.Results:the amount of inoculation,p H value and temperature had the greatest effect on the aflatoxin degradation by Paenibacillus pabuli E1.Three factors and three levels are used to optimize the influencing conditions and experimentally obtain the response value of each combination condition.According to regression equation analysis and significance analysis,when the temperature,the inoculation amount and the p H value are respectively 33.767℃,3.212%and6.508,the degradation rate of aflatoxin degradation by Paenibacillus pabuli E1 is the best,with a degradation rate of 89.30%.This study provides an efficient and feasible method for the aflatoxin degradation in grains and grain derivatives.（3）To study the ability of aflatoxin degradation by Paenibacillus pabuli E1 in DDGS and the changes of nutrients in DDGS.The inoculum 2%,the p H 7 and the temperature 27°C cultivate for 24 hours to provide fermentation broth.The fermentation broth was inoculated into DDGS at 3.2%,and solid fermentation was carried out under the conditions of humidity≤20%and 33.8℃for 96h.After fermentation,the changes in nutrients in DDGS were measured.Results:after 96h,the aflatoxin degradation rate in DDGS by Paenibacillus pabuli E1 reached91.27%.After solid fermentation,compared with before fermentation,,the content of crude cellulose decreased by 1.01%,the content of crude protein increased by 6.34%and the content of crude fat increased by 1.89%.Compared with other documents,it shows that the bacteria has high degradation efficiency,strong safety,and the fermentation conditions are not harsh,and it has a good development prospect in practical applications.