Biodegradation of Low- and High-Density Polyethylene Films by Microbacterium Barkeri Sh20

Abstract

Polyethylene waste contamination is one of the most concerning environmental issues not only in India but also in world. Microbial degradation is one of the safest and environment friendly process to degrade polyethylene among other major types degradation methods such as thermo-oxidative degradation and photo-degradation. The present research focused on the isolation, enrichment, and characterization of polyethylene-utilizing bacteria, not screen as far for biodegradation, and evaluation of its degrading capacity on polyethylene. A bacterial strain (TN2) was isolated from a motor-oil contaminated soil. The biochemical characterization of the strain was based on an automated microbial identification system. Strain TN2 was identified through 16SrRNA gene sequencing, which shows strain was closely related to Microbacterium genus and identified as Microbacterium barkeri SH20 (Accession No. KY887791.1). To examine the degradation capacity of isolated strain, it was used for biodegradation studies on two types of polyethylene films i.e. LDPE as well as HDPE (low and high density polyethylene respectively) HDPE (high-density polyethylene) for 30 days. The film samples were analyzed after bacterial strain incubation based on the weight loss percentage and the Keto & Ester Carbonyl Index (via Fourier transform infrared spectroscopy- FTIR). The highest decrease in weight loss percentage was calculated of PE-S1 HDPE film samples i.e 0.985±0.23%, as weight loss represents a qualitative evaluation of biodegradation. FTIR studies shows changes IR peaks of C=O regions and Keto & Ester Carbonyl Index was found to decrease in HDPE films (PE-S1) compared to other two LDPE (PE-S2) and HDPE films (PE-S3) shows degradation of polyethylene. The research established that Microbacterium barkeri SH20 (TN2) is a novel bacterial strain that can degrade polyethylene films. Hence, it can be used in future biodegradation studies and field trails.