Biodegradation of Waste Plastic by Bacterial Consortium from Contaminated Soil and Cow Dung

Abstract

The growing issue of plastic pollution on a global scale is need of attention which cannot be handled with conventional waste management. Bioremediation presents itself as a promising environmentally friendly method that can make a difference in fighting the causes of plastic pollution. The large-scale accumulation of plastic) within the Panskura municipality has become a potential risk to the environment and public health. In this research, the biodegradation of plastic municipal wasteswas using microbial consortia derived from plastic contaminated soil and cow dung. The microbial isolates, Pseudomonas spp, Bacillus spp, Stenotrophomonas spp, and Paenibacillus spp, were screened for plastic degrading activities with 51 degradation tests. The isolates were then assessed via weight loss measurement, scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry. Results exhibited up to 36% weight loss in polypropylene (PP) after thirty days, with the consortia doing better than single strain actions. SEM showed evidence of surface erosion. These microbes’ consortia, just like those sourced from the Panskura plastic waste dump site are useful for overcoming the challenges of municipal plastic waste through biological means.

Introduction

Global plastic production exceeds 400 million metric tons annually, with LDPE, HDPE, and PP constituting over 60% of plastic waste, heavily polluting landfills and ecosystems. Traditional disposal methods like landfilling and incineration release harmful toxins and microplastics, prompting sustainable alternatives such as microbial biodegradation. Certain bacteria, including Bacillus, Pseudomonas, Stenotrophomonas, and Paenibacillus, have shown potential to degrade resistant plastics by enzymatically breaking down polymers into non-toxic products.

This study isolates these bacteria from plastic-contaminated soil and cow dung in Panskura, India—an area with severe plastic pollution. The microbes were screened using minimal media containing powdered HDPE, LDPE, and PP as sole carbon sources. Selected isolates demonstrated plastic degradation via the formation of clearance zones and were further characterized morphologically and biochemically.

Plastic biodegradation was quantitatively assessed by measuring weight loss of sterilized plastic samples incubated with bacterial cultures over 30 days at 27°C and 50°C. Surface changes post-degradation were analyzed using field emission scanning electron microscopy (FE-SEM), confirming microbial breakdown.

Results identified five efficient plastic-degrading isolates, with three thriving at 50°C and two at 27°C. Soil-derived bacteria made up the majority, reflecting adaptation to plastic-polluted environments, while cow dung provided a rich but underutilized source of lignocellulolytic microbes aiding degradation.

This work highlights the potential of tailored microbial consortia from ecologically relevant niches as an eco-friendly solution for managing plastic waste in urban areas.

Conclusion

This study underscores the significant potential of tailored microbial consortia, derived from plastic-contaminated soil and cow dung, to accelerate the biodegradation of persistent municipal plastic waste. The demonstrated 36% weight reduction in polypropylene, coupled with SEM evidence of structural degradation, highlights the superior efficacy of consortia over individual strains. By leveraging microbes from adaptive environments, this approach offers an eco-friendly, scalable strategy to address plastic accumulation in municipalities aligning with global sustainability goals. These findings advocate for integrating microbial solutions into waste management frameworks, providing a viable pathway to mitigate environmental and public health risks while reducing reliance on conventional methods. Further optimization and field trials could enhance biodegradation rates, advancing this technology toward practical, real-world application.

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Copyright

Copyright © 2025 Gargi Banerjee, Saurabh Kumar Mehta, Sirsendu Bikash Maiti. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.