Screening of Plant-Derived Actinomycetes with Antifungal Activity

— A screening procedure was implemented to identify actinomycetes that synthesize antifungal antibiotics. Plants indigenous to Hiroshima Prefecture were used instead of soil to diversify the source of actinomycete isolates, which has conventionally been utilized in previous studies. During the primary screening, putative actinomycetes isolated from plants were separated based on their biochemical traits, acquiring two hundred and eighty-two actinomycete strains. Subsequently, for the secondary screening process, five fungal strains ( Saccharomyces cerevisiae , Schizosaccharomyces pombe , Aspergillus oryzae , Mucor hiemalis , and Rhizopus stolonifer ) were used to evaluate the antifungal activity. The findings revealed that, out of the two hundred and eighty-two strains, five actinomycetes demonstrated antifungal activity against all tested fungi. Lastly, a tertiary screening compared the antifungal effects of five actinomycetes demonstrating activity against all tested fungi. More specifically, a comparison was made regarding the potency of antifungal substances produced by the five strains acquired, using commercially available antifungal agent amphotericin B as an indicator. The results of tertiary screen confirmed that HIT18, among the five actinomycetes, possessed a broad antifungal spectrum.