Microbial degradation of low density polyethylene

Abstract

Low‐density polyethylene (LDPE) is potential source of environmental pollution. In this study, biodegradation of LDPE was achieved by employing fungus and actinobacteria isolated from waste dumping site. Among all the isolates, two potential strains were obtained through enrichment technique. Based on 18S rRNA and 16S rRNA analyses the isolated strains were identified as Aspergillus nomius and Streptomyces sp., respectively. The biodegradation of LDPE was determined by evaluating weight loss and morphological changes of the LDPE samples. The isolated strains; Aspergillus nomius had the capacity to degrade 4.9% and Streptomyces sp. showed 5.2% of weight loss of LDPE films respectively. Weight loss of LDPE film after inoculation of isolates in degradation medium indicated that it was capable of using polyethylene as carbon and energy source. CO2 evolution was checked after degradation of polyethylene pieces, the level of CO2 reached 2.85 g L−1 in the presence of Aspergillus nomius and Streptomyces sp. produced 4.27 g L−1. Sophisticated instrumentation was used like atomic force microscopy, Fourier transform infra‐red spectroscopy (FTIR). The breakdown products of the LDPE film after exposure to the isolates was recorded employing GCMS. FTIR spectrum of LDPE film confirmed changes in the presence of chemical groups like amine, alkanes, phenols, and alcohol after degradation of LDPE films by Aspergillus nomius and Streptomyces sp. and the most prominent structural changes of the spectrum were observed in the LDPE sample after 90 days of degradation. The results affirmed the isolates were capable of degrading LPDE films efficiently. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 147–154, 2017