Asian Journal of Microbiology, Biotechnology & Environmental Sciences Paper

Vol 21, Issue 4, 2019; Page No.(1057-1062)

ASSESSMENT OF GLUCONIC ACID PRODUCING FUNGI AS BIOCONTROL AGENTS AGAINST AFLATOXIGENIC ASPERGILLUS FLAVUS AND ASPERGILLUS PARASITICUS

RAMYA KRISHNAMURTHY, PADMA, P. RAND KAVITHA DHANDAPANI

Abstract

Mycotoxin producing fungi such as Aspergillus flavus and Aspergillus parasiticus are a serious menace in crop fields as they cause contamination of staple foods and make them unfit for consumption. Biocontrol measures have been effective for combating many fungal infections. In this study, gluconic acid producing fungi such as Gliocladium virens, Scopulariopsis canadensis and Penicillium funiculosum were chosen as candidates and were assessed for their biocontrol activity against toxin producing Aspergillus flavus and Aspergillus parasiticus under in vitro conditions. This involved the evaluation of radial growth reduction of A. flavus and A. parasiticus in various solid media when cocultured with the chosen candidate fungi. Monitoring aflatoxin concentrations, mycelial dry weight and spore morphology changes of the toxigenic fungi, along with pH measurements during coculture facilitated to discern the potential of each antagonist fungi. A maximum antagonism of 80.1% was exhibited by G. virens against A. parasiticus compared to other chosen fungi. The efficacy of the candidate fungi was also evaluated by simultaneous co-culture on corn kernels as substrate which resulted in about 95.5% inhibition in toxin production by A. parasiticus with G. virens. This indicates that G. virens proves to be an efficient competing strain against aflatoxigenic fungi.