Biodegradation of Low Density Polyethylene by Selected Bacillus sp.

Abstract

The necessity of environment friendly disposal policies designed for the biodegradation of synthetic plastics is tremendously crucial and need attention in the present scenario, considering the hazardous impact of widely used packaging material such as Low Density Polyethylene (LDPE) on the environment. Our study aims to explore the degradation of LDPE by three strains of Bacillus sp. i.e ISJ51, ISJ55 and ISJ57. The magnitude of biodegradation was evaluated by several techniques comprising weight loss of the polyethylene sample, reduction in bacterial hydrophobicity and estimation of biomass attached to the polyethylene film. The maximum biodegradation i.e., 1.5%, as well as protein content (0.75 μg/cm2) of bacterial biofilm adhered on LDPE was observed in Bacillus sp. strain ISJ55 after 60 days of treatment. ISJ55 also demonstrated more hydrophobicity in comparison to ISJ51 and ISJ57, since, a 20.3% reduction in culture turbidity was specifying better attraction towards hydrophobic substances. SEM analysis revealed that ISJ55 exhibited morphological changes in polyethylene surface while FTIR images showed functional changes after an incubation of 60 days. The establishment of biofilms on polyethylene surface and adhesion capabilities of bacteria are deliberated as the first step in the process of biodegradation. Therefore these results show that the isolate ISJ55 can colonize, modify and utilize LDPE as a sole carbon source, signifying the potential of Bacillus sp. to degrade LDPE film. This manuscript also paves the way for future studies on biodegradation to resolve the universal issue.