Establishment of a screening method for degrading aflatoxin M1 strains and identification of the degradation strain

In order to realize the biodegradation of Aflatoxin M1 ( AFM1) , a screened method of strains used to degrade AFM1 in the environment was established and an ideal degradation strain was obtained. The results showed that: 37 strains were primarily screened from 300 soil or fecal samples collected from farmland, grain depot and cattle farm, which could grow on the medium with coumarin as the sole carbon source.The degradation rate was determined by liquid chromatography.3 strains with degradation rate of more than 50% were obtained.Furthermore, the growth conditions and the tolerance of the strains obtained from the double screen were tested. The strain 102807 was obtained with the degradation rate of 78.6%, which had a fast growth, good growth, long period of stability, good thermal stability of the degradation process, high acid and alkali resistance.The strain 102807 was identified as Cellulosimicrobium cellulans through colony and cell morphological, physiological and biochemical characteristics and phylogenetic analysis of 16 S r DNA sequence. Cellulosimicrobium cellulans with biological degradation function of AFM1 is discovered for the first time.