Isolation and characterization of Bacillus amyloliquefaciens YL-1 with ochratoxin A degradation ability and biocontrol activity against Aspergillus westerdijkiae

Abstract

Ochratoxin A (OTA), a toxic secondary metabolite mainly produced by Aspergillus and Penicillium species, is often found in food and agricultural products. Microbiological degradation appears to be a promising method for mycotoxins detoxification. In the present work, a bacterial strain YL-1 with OTA removal ability was isolated and identified to be Bacillus amyloliquefaciens based on 16S rRNA and gyrA gene sequences analyses. Up to 79.7% of OTA with an initial concentration of 2.5 μg/mL could be removed in liquid medium by this isolated bacterium in 48 h. Extracellular enzymatic degradation is suggested to be mainly responsible for the OTA removal ability of B. amyloliquefaciens YL-1, with lactone-opened ochratoxin α as the possible degradation product. Moreover, B. amyloliquefaciens YL-1 could inhibit the fungal growth of Aspergillus westerdijkiae both on agar plate and rice grains. These findings indicated that B. amyloliquefaciens YL-1 could be considered as a promising biological agent against OTA contamination and A. westerdijkiae growth in cereal grains.