Microbial Inoculant-Driven Degradation of Microplastics Associated With Garbage Environment and Assessment of Degradation Product Toxicity.

This investigation revealed that the application of specific microbial inoculants could facilitate the effective biodegradation of polyethylene terephthalate (PET) microplastics collected from urban garbage sites, resulting in non-toxic end products. We employed Azotobacter chroococcum (MTCC 3853), Rhizobium leguminosarum (MTCC 9766), Azospirillum brasilense (MTCC 4036), and Trichoderma viride (MTCC 9681) for PET microplastics degradation and assessed their degradation efficacy through a series of controlled in vitro batch experiments. The study encompassed quantitative analysis of PET weight loss, detailed chemical profiling of degradation intermediates and products, biofilm formation assessment, microbial growth monitoring, and measurement of plastic-degrading enzyme induction. To comprehensively evaluate environmental safety, phytotoxicity assays were performed on Vigna mungo and Vigna radiata, while zebrafish embryos and adults were subjected to acute and embryonic toxicity tests. A. chroococcum (MTCC 3853) was identified as the most efficient strain, showing the greatest reduction in PET mass, enhanced biofilm formation, sustained microbial growth, and peak enzymatic activity, with no detrimental effects on plant or aquatic models, confirming the safety of the biodegradation process. These results underscore the potential of A. chroococcum (MTCC 3853) as a powerful and environmentally friendly solution for microplastic remediation in urban environments.