College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China.
Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China.
Environ Sci Technol. 2022 Sep 6;56(17):12267-12277. doi: 10.1021/acs.est.2c02782. Epub 2022 Aug 11.
Microplastics in the environment can be colonized by microbes capable of forming biofilms, which may act as reactive coatings to affect the bioaccessibility of pollutants in organisms. This study investigated the dynamic evolution of biofilm colonization on microplastics and its impacts and mechanisms on the bioaccessibility of microplastic-associated sulfamethazine (SMT) microcosm incubation in surface water and sediment. After 60 days of incubation, the microbial communities formed in microplastics were distinct and more diverse than those untethered in surroundings, and photoaging treatment decreased the affinity of biofilms on microplastics due to decreased hydrophobicity. Biofilm formation further enhanced the desorption and bioaccessibility of microplastic-sorbed SMT in organisms. experiments indicated that the critical effects were mainly related to the stronger interaction of gastrointestinal components (i.e., pepsin, bovine serum albumin (BSA), and NaT) with biofilm components (e.g., extracellular polymer substances) than with the pure surface of microplastics, which competed for binding sites in microplastics for SMT more significantly. Photoaging decreased the enhancing effects of biofilms due to their lower accumulation in aged microplastics. This study is the first attempt to reveal the role of biofilms in the bioaccessibility of microplastics with associated antibiotics and provide insights into the combined risk of microplastics in the environment.
环境中的微塑料可以被能够形成生物膜的微生物定植，生物膜可能作为反应性涂层，影响生物体内污染物的生物可及性。本研究调查了生物膜在微塑料上的动态演化及其对地表水和沉积物中微塑料相关磺胺甲恶唑（SMT）微宇宙孵育中污染物生物可及性的影响和机制。孵育 60 天后，微塑料上形成的微生物群落与周围未束缚的微生物群落明显不同，且多样性更高，光老化处理由于疏水性降低而降低了生物膜对微塑料的亲和力。生物膜的形成进一步增强了微塑料吸附 SMT 在生物体内的解吸和生物可及性。实验表明，主要的关键影响与胃肠道成分（如胃蛋白酶、牛血清白蛋白（BSA）和 NaT）与生物膜成分（如胞外聚合物物质）之间的相互作用比与微塑料纯表面之间的相互作用更强有关，因为前者更能显著竞争微塑料中 SMT 的结合位点。光老化降低了生物膜的增强作用，因为其在老化微塑料中的积累减少。本研究首次尝试揭示生物膜在抗生素相关微塑料生物可及性中的作用，并深入了解环境中微塑料的复合风险。
