The microbial and physicochemical interactions of soils in the degradation of buried polyethylene pipes in Colombia

The widespread use of polyethylene (PE) in industries such as agriculture and construction poses environmental challenges due to its recalcitrance in natural ecosystems. This study focuses on the microbial and physicochemical interactions of soils from Colombia, in the degradation of buried polyethylene pipes, combining molecular, microbiological, and physicochemical approaches to understand soil–microbe–plastic dynamics. Soil samples were collected from sites with buried polyethylene pipes exhibiting degradation signs. Microbial communities were characterized using 16S rRNA and ITS sequencing, with Nanopore technology, to identify bacterial and fungal taxa. Additionally, microbiological analysis was performed by taking swabs from the surface of degraded pipes to directly observe microbial colonization. Fungal isolates were cultured on Potato Dextrose Agar (PDA) to correlate traditional isolation techniques with molecular findings. Soil physicochemical properties, including pH, moisture, redox potential, particle size distribution, and others, were analyzed. Polyethylene degradation was assessed through surface analysis by scanning electron microscopy (SEM). Bacterial phylum Proteobacteria and genera such as Pseudomonas, along with fungal genera such as Aspergillus and Fusarium, were identified as key players in soils with higher degradation rates. Microbiological analysis of pipe surfaces confirmed microbial colonization, consistent with soil sequencing data. Fungal isolates grown on PDA matched molecular findings, validating the integration of traditional and molecular approaches. SEM imaging revealed significant surface erosion and microbial colonization on the polyethylene pipes. Physicochemical analyses showed that soils with neutral pH and higher moisure content supported more active and diverse microbial communities. This study demonstrates the critical role of microbial activity and soil physicochemical properties in polyethylene degradation. The integration of microbiological, molecular, and physicochemical methods offers a comprehensive framework to advance sustainable strategies for managing plastic pollution in soil environments.