Enhanced peroxidase-mediated biodegradation of polyethylene using the bacterial consortia under H2O2-biostimulation

Abstract

Biotreatment is an environmentally friendly process for pollution control. A novel biotreatment process was investigated for the degradation of plastic wastes. The biodegradation of low-density polyethylene (LDPE) films using a bacterial consortium capable of peroxidase production in the presence of H2O2 was investigated for a 12-month period. Effective biodegradation was observed using the selected bacterial consortia; a 19.8% weight loss was detected during 12 months of biotreatment of the LDPE films. The daily addition of H2O2 to the bioreactor stimulated the microbial activity resulted in improving the weight loss to 22.5% due to the in-situ production of peroxidase. The number average molecular weight (Mn) decreased by 20.1 and 49.5% when the polyethylene sample was biotreated for 12 months in the absence and presence of H2O2, respectively. The depolymerization of the LDPE films during the biotreatment using the selected bacterial consortia was confirmed by increasing the value of polydispersity index. The morphological and structural analyses confirmed the efficient decomposition of the LDPE films using the selected bacterial species, showing that the selected bacteria could use the LDPE films and/or their degradation intermediates as carbon and energy sources. Overall, using a peroxidase-generating bacterial mixed culture is a promising biotechnique for the efficient biodegradation of the polyethylene wastes.