Biodegradation of polyethylene by an enriched microbial community from activated sludge

In the face of mounting global plastic pollution, especially concerning microplastics, to which biodegradation must be a sustainable solution. The key factor driving this technology is to explore efficient plastic-biodegraders from different habitats, among which activated sludge (AS) may be an important option since it holds diverse microorganisms occupying various ecological niches. Here we intend to enrich the plastic-degrading microorganisms from AS by using polyethylene (PE) plastic as the carbon and energy source. After a 28-day incubation, the weight loss of PE films reached 3% and the hydrophobicity decreased, indicating physical biodegradation. Moreover, Fourier-transform infrared spectroscopy (FTIR) results showed the formation of several new oxygen-containing functional groups on PE. Microbial analysis extracted 26 metagenome-assembled genomes (MAGs) from the enriched microbial communities. Among them MAG10, MAG21 and MAG26 displayed the increased abundance upon PE addition and harbored abundant genes related to carbohydrate transport and metabolism, suggesting their potential to degrade PE. Additionally, functional analysis revealed 14 plastic degradation-related genes, including oxidase, laccase, and lipase, indicating the significant potential in plastic degradation. Furthermore, a pathway for synergistic biodegradation of PE was proposed based on the potential PE degradation genes retrieved from MAGs. This work offers a promising and sustainable solution to plastic pollution by enriching the potential biodegradators from AS.