Inhibitory action of mycocins from Wickerhamomyces anomalus on filamentous fungi present in cornmeal

Abstract

Some species of filamentous fungi present in grain crops can be mycotoxigenic. Mycotoxins are secondary metabolites that are potentially carcinogenic, hepatotoxic, and nephrotoxic to humans and animals. In addition, they are mostly thermostable, i.e., they resist the processing and refining of grains. Wickerhamomyces anomalus is a yeast found widely in nature and was the first reported yeast capable of producing mycocins that act on both eukaryotic and prokaryotic microorganisms. Mycocins are glycoproteins that act on sensitive cells of other microorganisms without direct cell-to-cell contact. This study aimed to identify the filamentous fungi present in cornmeal and verify their inhibition against the mycocins of W. anomalus WA92, all the cornmeal samples analyzed (eight) presented colony-forming units (CFU) of filamentous fungi including some known as potential mycotoxin producers, and 10 fungal genera were identified—Acremonium sp., Alternaria sp., Aspergillus sp., Chrysosporium sp., Cladosporium sp., Fusarium sp., Mucor sp., Penicillium sp., Rhizopus sp., and Scopulariopsis sp. Tests were carried out on a solid medium containing the supernatant of mycocins from W. anomalus and showed total inhibition of the growth of these fungi. Mycocins from W. anomalus are a promising agent in the biocontrol of grain fungal populations.