Biological Control of Mycotoxigenic Fungi and Ochratoxin A by The In-Vitro Application of a Qatari Burkholderia cepacia Strain (QBC03)

Abstract

Mycotoxins are secondary metabolites synthesized by mycotoxigenic fungi belonging mainly to three major fungal genera that are Aspergillus, Fusarium and Penicillium. The latter mycotoxigenic fungi contaminate plants and different food commodities and cause various health concerns (carcinogenicity, mutagenicity, nephrotoxicity, etc...) due to their corresponding mycotoxins. One of the most studied mycotoxins is ochratoxin A (OTA) owing to its toxicity level (classified in 2B group as possible human carcinogenic). To remediate the mycotoxins' contamination, physical and chemical techniques can be proposed. However, the safest among all is the biological control approach. In this research, we have used the Qatari strain Burkholderia cepacia (QBC03) as a biological agent against mycotoxigenic fungi, and the strain has possessed a wide antifungal spectrum against 21 species from different genera. Additionally, the antifungal activity of QBC03's supernatant was explored on the fungal biomass and OTA synthesis of A. carbonarius in liquid media, and interestingly; both the biomass and OTA's concentrations were massively reduced upon treatment. The effect of QBC03's supernatant on the fungal spores' germination was examined as well, and it was shown that the conidial germination was completely inhibited. Moreover, the supernatant of QBC03 has induced morphological alteration in the mycelia of the fungal strain. The thermal stability of the antifungal compounds in QBC03's culture supernatant was investigated, and it was shown that metabolites of QBC03 were distinctively thermostable and they were still active even when heated at 100C. The findings of this research prove that Burkholderia cepacia strain QBC03 is an excellent candidate for the biological control of mycotoxigenic fungi and their mycotoxins particularly in local regions.