Exploring Antimicrobial Potency of Soil Actinobacteria from South Sulawesi, Indonesia

Actinobacteria, a significant group of soil microorganisms, are notable for producing bioactive compounds, including antibiotics. This study aims to explore the antimicrobial activity of actinobacteria isolated from unexplored areas in South Sulawesi, Indonesia. Twelve actinobacterial strains were evaluated for their antimicrobial potential versus Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 25922, and Candida albicans ATCC 10231 using the agar plug diffusion assay, which was performed based on their growth in agar media. Potential actinobacteria was extracted from the biomass and supernatant with ethyl acetate, and the infrared spectrum was observed via Fourier-transform infrared (FTIR). The findings demonstrated that the optimum secondary metabolite production time varied among strains, with maximum activity observed on specific growth days for different target microorganisms. Actinobacteria TTR22-029, exhibited the most potent antibacterial activity, on the six days of growth, particularly against S. aureus, which provide a diameter zone of inhibition of 16.83±0.3 mm. According to Fourier-transform infrared analysis, the ethyl acetate extracts of TTR22-029 revealed the presence of functional groups, including hydroxyl and carbonyl, which are generally linked to bioactive substances. These outcomes underline the prospect of actinobacteria from South Sulawesi as an origin of novel antimicrobial agents, emphasizing the importance of exploring diverse ecosystems for drug discovery. Further research is necessary to purify and characterize the bioactive compounds.