Bioactivity of secondary metabolites from microbes isolated from Idundi, traditionally fermented banana from Tanzania

Idundi is a traditionally fermented banana food usually consumed by women in North¬eastern Tanzania soon after child birth, believed to help in the healing of their wombs. This study was aimed at investigating the in vitro bioactivity of secondary metabolites produced by microorganisms associated with Idundi. Activity was investigated by agar well and paper disk diffusion methods and broth microdilution method. A total of 3 bacteria and 6 filamentous fungi were isolated from the traditional fermentation process of bananas in Mbaga village, Same, Kilimanjaro. Out of these, 4, (44%) produced bioactive medium polar extracts with a varying degree of antimicrobial activity against Escherichia coli, Staphylococcus aureus, Candida albicans, Aspergillus Niger and Cryptococcus neoformans known to be human pathogens. Two of the bacterial isolates producing bioactive extracts were identified to be Klebsiella oxytoca and Kluyvera cryocrescens on the basis of their 16S rDNA sequences. Two of the filamentous fungal isolates producing bioactive extracts were identified to be Trichoderma aureoviride and Rhizopus stolonifer on the basis of their ITS region sequences. Two yeast isolates namely; Candida pyralidae and Rhodotorula mucilaginosa were found to produce bioactive extracts which were active against the test organisms. Chemical profiling of the extracts revealed the presence of alkaloids, terpenoids, phenolics and sterols from the bacterial and fungal isolates and alkaloids and terpenoids from the yeasts isolates. In conclusion, antimicrobial activity of secondary metabolites from microbes associated with Idundi provides scientific corroboration for its therapeutic value.