Screening of Antagonistic Bacteria Against Aflatoxigenic Aspergillus flavus from Fermented Bean Paste

Abstract:

The mixture of broad bean and wheat flour during fermentation was used to screen antagonistic bacteria against aflatoxigenic Aspergillus flavus. A strain L4 with strong antifungal activity against the aflatoxin-producing Aspergillus flavus was selected using broadbean agar medium (BAM). According to its morphological, physiological and biochemical characteristics and 16S rRNA gene sequence homology analysis, L4 was identified as Bacillus subtilis. When L4 and Aspergillus flavus were co-cultured for 15 days, the weight of the mycelium and the production of aflatoxin B1 were both significantly lower than those of Aspergillus flavus cultured without L4. The accumulation of AFB1 was inhibited significantly, the values of the reduction was 93.7%. When L4 culture supernatant was mixed with the spore suspension of A. flavus at ratio of 1: 1 and then inoculated on corns, the germination and growth of A. flavus was inhibited completely.

Key words:Aspergillus flavus, Aflatoxin B1, Antifungal bacteria, Identification, Inhibitory activity