Biofilm formation on the polyethylene terephthalate plastic surface weathered under laboratory and real landfill conditions

Abstract

Plastic undergoes rapid colonisation in the environment, resulting in the formation of a biofilm necessary for further biodegradation. This study investigates the enrichment opportunities of biofilms formed on polyethylene terephthalate (PET) plastic surfaces incubated in landfill leachate for three months (PL-3), followed by three-month incubation in complex media (PLE1–6 and PLE2–6). The metagenomic analysis of biofilms revealed distinct differences in the microbial community structure. Incubation in leachate (PL-3) resulted in Nitrosomonas prevailing (31.66 %), while biofilms enriched in PLE1–6 and PLE2–6 contained Pseudomonas spp. at 41.89 % and 33.22 %, respectively. Fluorescence in situ hybridisation (FISH) microscopy analysis, using a probe design specific for Pseudomonas spp., was in line with metagenomic data and explored the distribution of this genus in the biofilms. PET bottles weathered under real landfill conditions also contained Pseudomonas spp., but to a lesser extent (10.67 % – 14.52 %) compared to laboratory enrichment. Two weathered PET specimens, sampled at different landfill sites, differed markedly in an abundance of Archaea. The overall enzymatic activity of the biofilm was measured by the fluorescein diacetate hydrolysis assay. By elucidating the impacts of nutrient additives on biofilm formation on PET plastic surfaces, one can gain a deeper comprehension of the mechanisms underlying biofilm development on plastic surfaces. That, in turn, is closely related to plastic biodegradation processes in landfill environments.