Characterization and GC-MS-Based Identification of Possible PVC Degradation Pathways of Bacteria for Sustainable Microplastic Bioremediation.

Abstract

Polyvinyl chloride (PVC), due to its persistent nature and the hazardous effects associated with chlorine content, poses global challenges like accelerated environmental pollution, public health crises and an increased economic burden. Its sustainable decontamination from the environment could be possible with the assistance of bacteria. The current study was initiated to achieve this sustainable goal. PVC-degrading bacteria were isolated via the serial dilution method using minimal salt medium (MSM) supplemented with PVC as a sole carbon source and characterized via 16S RNA gene sequencing analysis, growth curve and PVC strip weight loss assays, antibiotic sensitivity profiling, FTIR and GC-MS-based metabolic profiling. Five isolates, Achromobacter xylosoxidans SBBPVC1, Bacillus licheniformis SBBPVC2, Pseudomonas citronellolis SBBPVC3, P. stutzeri SBBPVC4 and Bacillus flexus SBBPVC5 were identified. All were fast-growing, with PVC degradation efficiency ranging between 20-50% per 30 days. The FTIR spectral comparison with the control clearly indicated peak variations in regions 1100-1250, 1370, 1460 and 1720-1740 cm^-1, corresponding to C-O and C-C, CH₃, CH₂ and C=O bond vibrations, validating PVC degradation in the presence of bacteria. GC-MS-based identification of four esters, i.e., 1-methyl heptyl, isooctyl, adipic acid, methyl octyl and octyl myristate esters, along with aliphatic alcohols and aldehydes, confirmed the degradation of PVC and its use as a carbon source by bacteria. Bacteria explored in current study could be used as bioremediating agents for PVC decontamination of the environment.