Asian Journal of Microbiology and Biotechnology

Dairy-waste-impacted soils may contain culturable bacteria with proteolytic activity, but reliable identification is necessary before their ecological or applied significance can be assessed. This study characterised a bacterial isolate, designated ES01, recovered from soil associated with a dairy-waste dumping area in Chennai, Tamil Nadu, India. Five morphologically distinct colony types were subcultured, and ES01 was selected for molecular and phenotypic examination. Genomic DNA was extracted, the 16S rRNA gene was amplified, and partial forward and reverse sequences were obtained by Sanger sequencing. Sequence comparison indicated 98.10% similarity to Priestia megaterium, and the sequence was deposited in GenBank under accession number PZ744528.1. The forward and reverse reads measured 862 and 520 bp, respectively. Phylogenetic analysis placed ES01 among Priestia reference sequences, supporting genus-level identification while leaving species-level assignment provisional. Microscopy and morphological examination indicated Gram-positive, rod-shaped, endospore-forming cells. The isolate was motile and tested positive for catalase activity, citrate utilisation and glucose and sucrose fermentation, whereas methyl red, indole and Voges–Proskauer reactions were negative. On skim-milk agar, clear zones surrounding bacterial colonies indicated extracellular casein hydrolysis under the conditions tested. The results provide an initial molecular, morphological and biochemical characterisation of isolate ES01, together with qualitative evidence of proteolytic activity. Whole-genome analysis and quantitative enzyme assays are needed to resolve its species identity and evaluate its functional relevance.