Isolation and characterization of a Bacillus amyloliquefaciens strain with zearalenone removal ability and its probiotic potential

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by Fusarium species, which has been shown to be associated with reproductive disorders in livestock, and to a lesser extent with hyperoestrogenic syndromes in humans. The aim of this study was to characterize a Bacillus amyloliquefaciens strain with ZEN removal ability. A pure culture of a strain designated LN isolated from moldy corn samples showed a high ZEN removal capability. Based on microscopic observations, biochemical characteristics, and phylogenetic analysis of the 16S rRNA gene sequence, LN was identified as B . amyloliquefaciens . After incubation of B . amyloliquefaciens LN in Luria-Bertani (LB) medium containing 3.5 ppm of ZEN, the ZEN concentration fell below the detection limit within 24 h. In ZEN-contaminated corn meal medium, B . amyloliquefaciens LN decreased ZEN concentration by 92% after 36 h of incubation. In phosphate-buffered saline (PBS) containing 5 ppm of ZEN, B . amyloliquefaciens LN reduced the ZEN concentration from 5 ppm to 3.28 ppm immediately after coming into contact with ZEN, and further reduced the ZEN concentration to 0.36 ppm after 4 h of incubation. The amounts of ZEN adsorbed by the cells of B . amyloliquefaciens LN did not increase with the extension of incubation time, indicating that B . amyloliquefaciens LN not only possessed ZEN adsorption ability, but also exhibited the ability to degrade ZEN. In addition, B . amyloliquefaciens LN was non-hemolytic, non-enterotoxin producing, and displayed probiotic characteristics including acidic tolerance, bile salt tolerance, and anti-pathogenic activities. These findings suggest that B . amyloliquefaciens LN has a potential to be used as a feed additive to reduce the concentrations of ZEN in feedstuffs.