Polyethylene (PE) microplastic, which is detected in various environmental media worldwide, also inevitably enters wastewater treatment plants, which may have an impact on anaerobic processes in wastewater treatment. In this work, the effect of PE microplastics on anaerobic sulfur transformation was explored. Experimental results showed that PE microplastics addition at 0.1%− 0.5% w/w promoted HS production by 14.8%−27.4%. PE microplastics enhanced the release of soluble organic sulfur and inorganic sulfate, and promoted the bioprocesses of organosulfur compounds hydrolysis and sulfate reduction. Mechanism analysis showed that PE microplastics increased the content of electroactive components (e.g., protein and humic acids) contained in extracellular polymeric substances (EPS). In particular, PE microplastics increased the proportion and the dipole moment of α-helix, an important component involved in electron transfer contained in extracelluar protein, which provided more electron transfer sites and promoted the α-helix mediated electron transfer. These enhanced the direct electron transfer ability of EPSs, which might explain why PE microplastics facilitated the bioprocesses of organosulfur compounds hydrolysis and sulfate reduction. Correspondingly, metagenomic analysis revealed that PE microplastics increased the relative abundance of S producers (e.g., and ) and the relative abundance of functional genes involved in anaerobic sulfur transformation (e.g., and ), which were beneficial to HS production in anaerobic system.

中文翻译：

---

聚乙烯微塑料暴露影响厌氧系统中硫迁移转化


在全球各种环境介质中检测到的聚乙烯（PE）微塑料也不可避免地进入废水处理厂，这可能对废水处理中的厌氧过程产生影响。在这项工作中，探讨了PE微塑料对厌氧硫转化的影响。实验结果表明，添加 0.1%−0.5% w/w 的 PE 微塑料可促进 HS 产量提高 14.8%−27.4%。 PE微塑料增强了可溶性有机硫和无机硫酸盐的释放，促进了有机硫化合物水解和硫酸盐还原的生物过程。机理分析表明，PE微塑料增加了胞外聚合物（EPS）中电活性成分（例如蛋白质和腐殖酸）的含量。特别是，PE微塑料增加了细胞外蛋白中参与电子传递的重要成分α-螺旋的比例和偶极矩，提供了更多的电子传递位点，促进了α-螺旋介导的电子传递。这些增强了 EPS 的直接电子传递能力，这可能解释了为什么 PE 微塑料促进了有机硫化合物水解和硫酸盐还原的生物过程。相应地，宏基因组分析表明，PE微塑料增加了S生产者的相对丰度（例如， 和 ）以及参与厌氧硫转化的功能基因（例如， 和 ）的相对丰度，这有利于厌氧系统中HS的产生。