Molecular Genotyping, 16S rRNA Sequencing, and Evolutionary Matrix of Streptomyces sp. Strain ANU-27 Isolated from Estuarine Mangrove Sediments

Abstract

Estuarine mangrove environments are unique, highly dynamic habitats harboring a rich and unexplored diversity of bioactive actinobacteria. In this study, we highlight the extensive molecular identification, genetic sequencing, and evolutionary positioning of the bacterial isolate ANU-27, which exhibited superior broad-spectrum antimicrobial efficacy during initial phenotypic screenings. Genomic DNA was successfully extracted using the CTAB-lysozyme methodology, yielding634±32 µg/gof high-integrity DNA with a distinct genomic G+C content of 55.1% calculated via thermal denaturation midpoint (Tm= 92.3C).The 16S rRNA gene locus was targeted and amplified via PCR utilizing 27F and 1492R universal primers, generating a sharp ~1500 bp amplicon. Bidirectional Sanger sequencing resolved a definitive sequence spanning 1177 nucleotides with a high ribosomal G+C ratio 59.13%. Comprehensive homology mapping via NCBI BLASTn paired with a1000-replicate Maximum Parsimony cladogram clustered the strain with 100% sequence identity( E-Value = 0.0) within the genus Streptomyces, revealing an immediate phylogenetic node shared with Streptomyces maritimus strain SBK2-IR9 and Streptomyces rochei strain ABU8. These findings firmly clarify the taxonomic assignment of strain ANU-27, spotlighting its high secondary metabolic and biotechnological promise.