Growth Inhibition of Aflatoxigenic Molds and Biodegradation of Aflatoxin B1 by Certain Bacterial Isolates

Abstract

AFLATOXIN B1 (AFB1) is mutagenic, carcinogenic, and harmful to humans and animals. Different physical and chemical methods have been proposed to reduce mycotoxins but few have been approved for practical application. This study investigated the possible use of certain bacterial species were isolated from different agricultural soils as biological control agents against the growth of toxigenic Aspergillus flavus and Aspergillus parasiticus isolated from sorghum and peanuts as well as biodegradation of aflatoxin B1 (AFB1). Out of these 30 bacterial isolates, 6 isolates showed that have antagonistic effects against the aflatoxigenic fungi but with varying efficiencies. The six different isolates were screened for their ability to degrade AFB1. Out of 6 isolates, one isolate showed high reduction activity of AFB1. Maximum antifungal activities were observed in one isolate was identified as Staphylococcus lentus. S. lentus completely prevented the A. flavus and A. parasiticus growth and completely degraded AFB1 in Liquid Culture. LC-MS/MS analysis revealed that S. lentus resulted in a 96.54% degradation of AFB1, but no products has been detected. In practical application, it was found that S. lentus at concentration of 10 and 25mL kg-1 were completely prevented the growth of A. flavus and A. parasiticus in sorghum and peanuts, respectively, consequently no aflatoxin were produced. According to our information, this is the first study to prove that Staphylococcus lentus has the capability to inhibit the growth of Aspergillus flavus and Aspergillus parasiticus by 100% and degrading AFB1 by 96%.