Bioprospecting and phylogenetic analysis of <i>Priestia flexa</i> AW3: an industrially significant amylase-producing bacterium from unexplored contaminated soil in Layyah

In spite of wonderful industrial applications of microbial enzymes, still most of habitats in various parts of world are unexplored for bioprospecting of industrial potent microbes. This study represents the first bioprospecting effort in Layyah district to explore indigenous bacterial diversity, enzymatic potential, and phylogenetic relationships in untapped contaminated soil habitat. Contaminated soils serve as reservoirs of industrially significant bacteria with unique enzymatic degradation capabilities, offering solutions for sustainable industrial applications and environmental remediation. An effort for comparative bioprospecting-based study for bacterial diversity exhibiting amylase potential across unaddressed contaminated soil samples [industrial, household, poultry, and animal waste (AW)] using qualitative and quantitative methods, was conducted. AW-contaminated soil exhibited the highest bacterial load (2.51 × 1010 CFUs) and amylase activity (51, amylase zones), whereas industrial waste soil showed the lowest CFUs (1.24 × 1010). Household waste soil, however, displayed the greatest Shannon diversity index (H'= 2.192262) for amylase-producing bacteria. Among isolates, Priestia flexa AW3 (OQ446563) demonstrated exceptional amylase production, forming 30 mm hydrolysis zones on starch agar and achieving optimal activity (1.76 ± 0.05 OD; 1.23 ± 0.03 AU/mL) at pH 7 and 37°C after 48 h. Notably, the strain retained enzymatic stability under extreme conditions, temperature up to 50°C, NaCl concentrations (0.5%-10%), and a broad pH range. Phylogenetic analysis via 16S rRNA sequencing confirmed its identity as P. flexa. This study underscores the untapped potential of contaminated soils in Layyah as sources of robust industrial microbes and highlights the value of bioprospecting in discovering novel bacterial strains for biotechnology and environmental sustainability. One-Sentence Summary: Bioprospecting for industrially important bacteria with unique enzymatic potential from untapped habitats is highly needed to solve sever environmental problems.