Screening And Identification Of Zearalenone Degrading Bacteria And Its Degrading Characterisics

Zearalenone (Zearalenone, ZEN), also known as F-2 toxin, is a kind of secondary metabolites mainly produced by Fusarium. It is widely present in milk and cereals such as wheat, sorghum, corn, barley and oats. It not only affects the economic value of crops, decrease the nutritional value, but also threats health of humman and animals. Currently, there are many methods to remove and reduce ZEN’s toxicity, such as physical, chemical and biological methods. But the traditional physical and chemical methods cannot remove toxins specifically and the removal efficiency is not high. The biological method overcome these disadvantages of the traditional methods, and become the most effective and feasible method, and thus become the focus and hotspot of researchers.In this paper, we isolated a strain that has the ablility to degrade ZEN and we deeply studied the degradation characteristics of this strain. There are three parts in this paper.The first part:purification of ZEN and screening of ZEN-degrading strain. We purified the ZEN toxin and did some research on the effect of defferent purification column in extracting ZEN from wheat. The results showed that the amino column was the most suitable purification column. LC detection conditions were as follows:gradient elution procedure,mobile phase:methanol and ammonium acetate in water; Flow rate:0.2 mL/min. MS detection conditions:electrospray ionization (ESI), the positive ion scan, multiple reaction monitoring (MRM). We collected 96 samples from Huai’an, Jiangsu Academy of Agricultural Sciences, Yangzhou in Jiangsu Province.Finally we isolated 14 strains which can degrade ZEN. Strain C4-1 had the highest degradation rate with higher than 90%.The second part:the identification of ZEN-degrading strains. The strain which has degardation rate of higher 90% was purified and then indentified through 16SrDNA sequence.The result showed that the strain belongs to Bacillus spp., and then the strain was named C4-1.The third part:the research on ZEN degradation characteristics of strain C4-1. The results showed that the optimal medium is MSB medium, the optimal temperature is 35℃, the optimal pH is 7.0, the inoculum concentration was 10%. The degradation rate can reach to 99% after culturing for 96 hours.