Synergistic Microbial Degradation of Microplastics and Toxic Dyes Showing Potential Reuse of the Degraded Dye Metabolites

Contamination of water through microplastics/polyethylene (PE) and textile waste effluents has become a global environmental threat that needs to be addressed sooner. This research aimed to assess a green approach to treat toxic dye effluents and PE using beneficial microbes. The bacterial strains were isolated from a habitat of waste effluent, collected from a Textile Dyeing Industry, Karachi Pakistan. Besides screening for laccase secretion, the isolates with an ability to degrade PE and transform toxic dye effluents into a reusable metabolite were identified by 16S rDNA sequencing as B. tequilensis M1 (Accession# MZ357709), B. subtilis M7 (Accession# MZ357959), Bacillus sp. (in: Bacteria) M8 (Accession# MZ360013), P. megaterium S8 (Accession# MZ422441) and Bacillus sp. (in: Bacteria) S5 (Accession# MZ382863). Average maximum bioremediation of 87% of reactive black and 97.6% of reactive blue dye were sufficiently taken place by B. tequilensis M1. The treated dye metabolites were comparatively effective and useful for irrigating radish plants, revealing bioremediation efficiency leading to potential use of biologically treated dye effluents. The reusability of treated toxic dye effluents was determined by phytotoxicity and seed germination analysis, along with water purity analysis experiments.