Polyethylene degradation by Ralstonia sp. strain SKM2 and Bacillus sp. strain SM1 isolated from land fill soil site

Low-Density Polyethylene (LDPE) is often widely used in packaging and wrapping because of its stability and durability. For decades, the plastic or synthetic polymer persists without deterioration in the soil. The aim of this analysis was to separate the bacteria from the soil of landfill and to evaluate the microbial degradation of the sheet of low-density polythene (LDPE) for 180 days. The microbial degradation was characterized by weight loss, alteration of pH in the media, Fourier Transform Infrared Spectroscopy (FTIR) and microscopic view. Molecular identification of bacteria was confirmed by phylogenetic analysis using 16SrRNA gene sequence. The bacteria were identified as Ralstonia sp. strain SKM2 and Bacillus sp. strain SM1. The weight loss in LDPE sheet by Ralstonia sp. strain SKM2 and Bacillus sp. strain SM1 was 39.2% and 18.9% respectively The pH of media was reduced from 7.12 to 6.67 for Ralstonia sp. strain SKM2 bacterium and 7.12 to 7.03 for Bacillus sp. strain SM1 bacterium. Clearly noticeable structural changes such as blackness, shrinkage, cracks, pits, and roughening of LDPE sheet surface were detected by microscope. FTIR also observed changes in the carbon bonds (especially alcohol), ether and alkane groups of LDPE sheet.Thus, the Ralstonia sp. strain SKM2 and Bacillussp. strain SM1 could be used as LDPE degrading microorganisms. (C) 2021 Published by Elsevier B.V.

Automated summary

In this study, bacteria were separated from landfill soil and their ability to degrade LDPE was evaluated. Ralstonia sp. strain SKM2 and Bacillus sp. strain SM1 were identified as effective LDPE-degrading microorganisms, causing weight loss and pH changes in the media. Structural changes in LDPE sheet were observed under microscope and FTIR analysis showed alterations in carbon bonds and groups.