VISHAL SAWARN, PRAMEETI, HEENA VERMA AND ARVIND KUMAR ARYA
Abstract
Municipal solid waste (MSW) harbors diverse microbial populations that can serve as valuable resources for discovering novel bioactive compounds and enzymes. This study aimed to isolate, characterize, and functionally assess bacteria from three active MSW dumping sites in Dehradun, India. Sixteen morphologically distinct bacterial strains were isolated and examined for biochemical properties, extracellular enzyme production, intra-isolate antagonism, antimicrobial activity against bacterial and fungal pathogens, and antibiotic susceptibility. Over half of the isolates were Gram-positive (56.25%), with catalase activity prevalent in 76.5% and diverse carbohydrate fermentation patterns observed. All isolates produced protease, while lipase, DNase, and lecithinase activities varied. Antagonism assays identified strains S8, S13, and S16 as potent inhibitors of other isolates. Strain S13 exhibited broad-spectrum antimicrobial activity, inhibiting Escherichia coli, Staphylococcus aureus, Salmonella spp., Candida albicans, and Candida glabrata. Antibiotic susceptibility profiling revealed sensitivity to ciprofloxacin, imipenem, and tetracycline in most isolates, with ampicillin resistance common. The co-occurrence of high enzyme productivity and antimicrobial activity in several strains highlights their potential for integrated waste treatment, biocontrol, and antimicrobial discovery. These findings underscore the value of MSW microbiota as source of biotechnologically relevant microorganisms and warrant further genomic and metabolomics exploration.