Screening and study of antifungal activity of leaf litter actinomycetes isolated from Ternate Island, Indonesia

ObjectiveTo characterize abundance of leaf litter actinomycetes from Ternate Island and to assess the antifungal activity of actinomycetes isolates against Candida albicans, Saccharomyces cerevisiae (S. cerevisiae), and Aspergillus niger.MethodsActinomycetes were isolated from leaf litter of Durio species, Syzygium aromaticum, Piper betle, Myristica fragrans, or Pandanus species and unknown plants. Actinomycetes isolates were cultured in a liquid medium. Bioactive compounds were extracted and tested against fungal using Beury-Kirby method with modification. Minimum inhibitor concentration and cell leakages were conducted. Actinomycetes that produced the highest antifungal activity were indentified using molecular sequence data in 16S rRNA gene.ResultsOut of 50 selected isolates, two isolates MG-500-1-4 and SR-2-2 has highest activity against S. cerevisiae. Concentration of material containing nucleic acids, proteins, Ca+ and K+ ions and morphological observations indicated that extracts of MG-500-1-4 and SR-2-2 caused cell leakage and invagination of S. cerevisiae cells. Based on 16S rRNA gene identification, MG-500-1-4 and SR-2-2 isolates are similar to Streptomyces misakiensis and Streptomyces tricolor respectively.ConclusionsTernate Island contains interesting biodiversity of actinomycetes that has potential use in agriculture, fisheries, and human health to reduce problem of fungal pathogen.