Microbial diversity analysis of municipal solid waste landfills soils of Delhi (NCR) and plastic dump sites of Uttar Pradesh region of India and their function prediction for plastic degrading enzymes.

Abstract

Municipal solid waste landfills are rich in plastic waste, fostering a unique microbial ecosystem distinct from natural habitats. This study aimed to investigate the microbial diversity at four landfill and plastic dump sites using a 16S rDNA metataxanomics approach, and to predict their potential for plastic degradation. Environmental DNA was isolated and analyzed through Illumina MiSeq sequencing. The results revealed a dominant presence of Pseudomonadota (47%) across all sites, with key genera including Streptomyces, Galbibacter, Alcanivorax, and OM190. The most abundant species were unclassified Chloroflexi bacterium, Galbibacter marinus, Gracilimonas amylolytica, and Teredinibacter sp. Alpha diversity analysis showed the highest species richness in plastic dump site in Utrathia (Lucknow), followed by Ghazipur landfill Site (Delhi), with low evenness across the bacterial communities. Beta diversity analysis, using Bray-Curtis and PCA, indicated distinct microbial profiles for each site. The PICRUSt analysis identified 402 genes related to nine enzyme categories involved in plastic degradation. Pearson correlation network analysis of top 1% genera highlighted positive associations between genera like Galbibacter, Alcanivorax, Thioalkalimicrobium, Idiomarina and Pseudomonas with peroxygenase enzyme. This study underscores the microbial diversity and functional potential of landfill microbes in plastic degradation, contributing to our understanding of the plastisphere microbiome in landfill environments.