Antagonistic Activity of Cowshed Bacillus sp. Bacteria against Aflatoxigenic and Sclerotic Aspergillus flavus

Mycotoxins produced by many food spoilage fungi cause serious damage to human as well as to livestock. Aflatoxins are one such group of mycotoxins produced by Aspergillus flavus in many agricultural and food products including rice. The fungus can virtually grow in any environment and also produces resistive structures such as sclerotia to overcome unfavourable environmental conditions. Hence, the need of the time is to control this toxigenic and sclerotic fungus through an eco-friendly approach. In the current study four biocontrol bacteria belonging to Bacillus species were isolated from Indian cow shed environment and these bacteria could efficiently control not only the mycelia growth of A. flavus but also the germination and growth of sclerotia. Both active bacterial culture broth and cell free culture filtrate could limit the growth of the fungus up to more than 90%. Older culture broth and filtrate lost their inhibition efficiency. Unlike many similar studies the current investigation emphasizes the importance of cowshed environment instead of cow dung and the control of sclerotia instead of fungal spores.