Molecular Characterization of Polythene Degrading Soil Microbe, Bacillus Cereus NAIMCC-B-01818

Pollution of soil and water by polyethylene, a saturated hydrocarbon and commonly known as polythene is a major threat to environment and human health in recent times. Several microorganisms occurring in the natural ecosystems are capable of degrading polythene. Biodegrading microbes were isolated from contaminated soil of IARI campus and a total of 12 isolates were screened for their ability to degrade polythene. Biodegradation was measured by mean weight loss of the polythene piece grown in the presence of the liquid culture of the microbial isolates for 30 days. 3% degradation of polythene was observed by the microbial isolate PL12. Based on biodegradation efficiency, PL12 was selected for further characterization and molecular studies. The microbial isolate PL12 was observed as rod-shaped gram positive bacterium. Carbohydrate utilization test confirmed the isolate PL12 to Bacillus genus and it was analyzed to be tolerant to alkaline (upto pH 10.0) and moderately high osmotic (2% sodium chloride) conditions. Further, 16S rDNA amplification and sequencing identified microbial isolate PL12 as Bacillus cereus. Using gene specific primers successful amplification of alkB (alkane monooxygenase B) gene was obtained in the isolate PL12, confirming the presence of alkylphenol degradation metabolic pathway in the isolate PL12.