AMB Volume 42, Issue 1, 2026 Pages 152-163 https://doi.org/10.59393/amb26420116
A Contribution to the Study of Streptomycete Diversity and Bioactive Potential in Unexplored Agricultural Landforms
Shanmugam I., Lakshmanan R., Venkatachalam S.K., Ramasamy J.
Actinomycetes are among the most significant prokaryotes due to their attribute in synthesizing bioactive secondary metabolites. Soil-derived actinomycetes, in particular, are notable candidates for the production of valuable compounds for pharmaceutical and industrial applications. In this investigation, actinomycetes were successfully isolated from the soil sample of agricultural landforms. Four different culture media were utilized to examine the influence of medium composition on the actinomycetes count. Among the tested media, starch casein agar yielded the highest actinomycete densities, ranging from 1.4 × 106 to 6.0 × 106 cfu g⁻¹ across all sampling sites. The lowest counts were recorded on Czapek-Dox agar, with values between 1.0 × 106 to 2.3 × 106 cfu g-¹. Sample 2 exhibited the maximum average actinomycete density (6.0 × 106 cfu g-¹), whereas sample 10 showed the lowest density of 1.4 × 106 cfu g-¹ on starch casein medium. The investigation revealed that 91.2% of the total isolates were tentatively classified as Streptomyces species and 8.8% as non-Streptomyces species. Out of 68 isolates, 15 strains were prioritized based on their bioactive potential and underwent morphological, physiological, and biochemical characterization. IA10 and IA17 were found to be more potent against tested clinical pathogens in the right-angle streak method and in 16s rRNA sequencing; both the isolates showed close resemblance with Streptomyces toxytricini and Streptomyces maritimus, respectively. This study highlights exploring the prevalence of the actinomycetes population in agricultural landforms and isolation of strains with antagonistic properties.
Keywords: actinomycetes, starch casein medium, 16s rRNA sequencing, Streptomyces toxytricini, Streptomyces maritimus
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