Biodegradation study of Polyethylene and PVC using naturally occurring plastic degrading microbes

One of the most serious man-made concerns today is the ever-increasing amount of plastic waste overwhelming the planet. The worldwide interest in using polymers consistently expanded over the years. Because of the plastic wastes thrown into the environment, outrageously the plastic pollution is increasing. In the present study, degradation of PVC and polyethylene-derived synthetic polymers has been carried out. The fungi and bacteria were isolated from the soil of the plastic waste environment and were used for the biodegradation of plastic films. Successful bacterial candidates for biodegradation were identified after screening. The bacterial strain Sb1 was identified as Bacillus licheniformis and Sb2 as Achromobacter xylosoxidans. The fungal strains Sf.1 and Sf.2 were identified as Aspergillus niger and Aspergillus glaucus, respectively. The degraded polymeric films were critically assessed by following the characterization methods like weight loss, FTIR and SEM. The results indicate that the polymers of polyethylene sample showed 32.2% degradation using bacterial strains and 40% using fungal strains in a time duration of just 4 weeks. PVC samples degraded 17 and 32% by fungal strains after 4 weeks. The changes in surface topography was confirmed by scanning electron microscopy and the changes in functional groups intensity was observed using the FTIR. Different parameters, varying temperature, pH, and inoculum concentration, were also evaluated, which implied that plastic waste treated by fungal and bacterial strains gives significant (p < 0.05) result in polymer degradation. As a result, the current research gave a scientific justification that bacteria and fungus could be further developed as promising candidates for plastic bioremediation.