Development of defined bacterial consortium as a bioaugmentation product for degrading mixed plastic wastes and plasticizers in simulated landfill

Abstract

Plastics and plasticizers pose significant waste management challenges, especially in landfills where degradation is slow. A plastic-degrading bacterial consortium offers a promising solution to accelerate this process. In this study, a bacterial consortium of Chitinophaga jiangningensis EA02, Nocardioides zeae EA12, Stenotrophomonas pavanii EA33, Gordonia desulfuricans EA63, Achromobacter xylosoxidans A9, and Mycolicibacterium parafortuitum J101, was cultivated in a molasses medium and applied to biodegrade polyethylene terephthalate (PET), polylactic acid (PLA), and phthalic acid esters (PAEs) in aqueous media and a pilot-scale simulated landfill at an actual landfill site to mimic real environmental conditions. The result found that increasing the levels of EA63 and A9 in an optimized ratio within the consortium improved the degradation efficiency. The effects of temperature, pH, and salinity on plastic and PAE biodegradation were evaluated. At 40 ± 3 °C, the consortium efficiently degraded PLA (31.25 %), PET (39.87 %), and PAEs (99.61 %) within 7 days. Under simulated landfill conditions, the consortium significantly reduced the gravimetric weight (38.84 %) and height (48.51 %) of the landfilled plastic waste after 179 days. A shelf-stable formulation of bacterial consortium product using phosphate buffer showed an estimated shelf life of 344 days at 30 ± 3 °C. This work successfully developed a shelf-stable bacterial consortium product for landfill bioaugmentation to demonstrate strong potential for future application in plastic waste management.