State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China.
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
Environ Pollut. 2022 Jan 1;292(Pt B):118485. doi: 10.1016/j.envpol.2021.118485. Epub 2021 Nov 10.
Recalcitrant plastics in the environment are gradually fragmented into weathered debris distinguished from their original state by the integrative action of influencing factors, such as UV light, heating and physical abrasion. As new artificial carbon-source substrates in aquatic ecosystems, plastic products can be colonized by biofilms and even utilized by microorganisms. To investigate the influences of weathering of plastics on the colonized biofilms, freshwater samples from the Yangtze River (Nanjing, China) were collected for biofilm incubation. Based on the characterization of plastics and biofilms, the effects of plastic surface properties on biofilm characteristics were revealed by the analysis of partial least squares regression (PLSR). Roughness was the principal influencing factor, while rigidity had the opposite effect to it. 16S rRNA gene high-throughput sequencing results indicated the high relative abundance of Cyanobacteria and rising proportion of harmful components (e.g., Flavobacterium) on photoaged polyethylene plastics. The microbial functional profiles (KEGG) predicted by Tax4Fun showed that the functions (e.g., membrane transport, energy metabolism, etc.) of biofilm on photoaged plastics were dissimilar with those on original ones. These findings suggested that the distinct microbial community and the adverse functional changes in biofilms on photoaged plastics potentially enhanced their environmental risks. On the other hand, 28-day cultured biofilms on original low-density polyethylene (LDPE) films were dominated by Exiguobacterium. The previously ignored potentials of this microorganism in rapidly accommodating to a hydrophobic substrate and its plastic degrading ability were both worthy of attention. Therefore, it is necessary to consider the weathering process of plastics in exploring the "plastisphere", and to give further insights into the double-edged nature of the "plastisphere".
在环境中，顽固的塑料会逐渐碎裂成风化碎片，这些碎片与原始状态不同，是受紫外线、加热和物理磨损等多种影响因素综合作用的结果。作为水生生态系统中的新型人工碳源基质，塑料产品可以被生物膜定殖，甚至被微生物利用。为了研究塑料风化对定殖生物膜的影响，从中国长江（南京）采集了淡水样本进行生物膜培养。基于对塑料和生物膜的特性分析，通过偏最小二乘回归（PLSR）分析揭示了塑料表面特性对生物膜特性的影响。粗糙度是主要影响因素，而刚性则相反。16S rRNA 基因高通量测序结果表明，在光老化聚乙烯塑料上，蓝藻的相对丰度较高，有害成分（如黄杆菌）的比例上升。Tax4Fun 预测的微生物功能图谱（KEGG）表明，光老化塑料上生物膜的功能（如膜转运、能量代谢等）与原始塑料上的功能不同。这些发现表明，光老化塑料上生物膜的独特微生物群落和不良功能变化可能会增加其环境风险。另一方面，在原始低密度聚乙烯（LDPE）薄膜上培养 28 天的生物膜主要由极端嗜盐菌属（Exiguobacterium）组成。这种微生物在快速适应疏水性基质和塑料降解能力方面的先前被忽视的潜力都值得关注。因此，在探索“塑料圈”时，有必要考虑塑料的风化过程，并进一步深入了解“塑料圈”的双刃剑性质。
