Construction of versatile plastic-degrading microbial consortia based on ligninolytic microorganisms associated with agricultural waste composting

The accumulation of plastic in ecosystems is one of the most critical environmental concerns today. Plastic biodegradation using individual microbial cultures has shown limited success, which can be improved by employing microbial consortia with appropriate enzymatic capabilities. This study aims to assemble and characterize microbial consortia using ligninolytic fungi and bacteria isolated from an agricultural waste composting process, with the goal of enhancing the efficiency of plastic biodegradation. The compost microbiome demonstrated plastic-degrading functionality, particularly during the raw material and cooling phases. Ligninolytic microorganisms from compost were characterized for enzymes related to plastic degradation and their ability to colonize plastic films. The genera Bacillus, Pseudomonas, Fusarium, Aspergillus, Scedosporium, and Pseudallescheria exhibited a wide range of activities associated with plastic biodegradation, making them candidates for consortia assembly. The biodegradation of polyethylene using single and consortium cultures revealed that consortia, particularly those combining Bacillus subtilis RBM2 with Fusarium oxysporum RHM1, enhanced degradation efficiency. Additionally, consortia targeting multiple plastics, including virgin and recycled linear low-density polyethylene (LLDPE), polyethylene terephthalate (PET), and polystyrene (PS), showed varying levels of success, with bacterial-bacterial combinations such as Pseudomonas aeruginosa RBM21 and Bacillus subtilis RBM2 demonstrating broad-spectrum plastic degradation. These findings underscore the potential of compost-derived microorganisms for plastic biodegradation and suggest that utilizing microbial consortia offers a promising approach to tackling plastic pollution.