Application of indigenous bacterial strains isolated from plastics-contaminated sites in high-density polyethylene degradation

Abstract Bacterial degradation of plastics is a promising environmentally sustainable approach that offers minimal environmental consequences in addressing the global problem of plastic pollution. A widely used organic polymer, high-density polyethylene (HDPE), has emerged as an environmental threat due to its lack of biodegradability. This paves the way for the present study, which investigated the degradation of HDPE sheets using bacterial strains isolated from a soil sample collected at the Kodungaiyur dumpsite, Chennai, India. Preliminary screening was performed to evaluate the ability of the isolated bacterial strains to grow in mineral salt medium (MSM) supplemented with HDPE and to assess their HDPE degradation potential. The weight loss percentage of the bacterial-treated HDPE sheet after the 60th day showed 8.28% ± 1.00, and surface morphological changes of cracks, grooves, and tiny holes were analyzed using SEM, which determined the HDPE sheet degradation. The FT-IR analysis of the bacterially treated HDPE sheet showed a reduction in the peak intensities of C-H stretching and C-H bending. The metabolites produced during the degradation process were analyzed using GC–MS, revealing the presence of predominantly linear and branched alkanes along with ester compounds. Molecular docking predicted interactions between GC–MS-identified compounds and the enzymes Acyl-CoA dehydrogenase, Hydrolase, and Oxidoreductase of Lysinibacillus massiliensis , indicating favorable enzyme-ligand interactions relevant to HDPE biodegradation. Overall, the findings demonstrate the potential of the isolated bacterial strains, particularly Lysinibacillus massiliensis RM3KVG, for HDPE biodegradation, supported by complementary weight-loss, SEM, FT-IR, GC–MS, and computational docking analyses.