State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Sci Total Environ. 2020 Feb 10;703:134899. doi: 10.1016/j.scitotenv.2019.134899. Epub 2019 Nov 2.
The macrolide antibiotic roxithromycin is widely detected in varying aquatic environments, especially in the wastewater systems, as an emerging contaminant and leads to significant impacts on the microorganisms involved. In this study, the impact of a shock load of roxithromycin on waste activated sludge (WAS) anaerobic digestion was comprehensively investigated. The biochemical methane potential tests showed that the methane production from WAS anaerobic digestion was significantly inhibited by roxithromycin. With the dosage of roxithromycin increasing from 0 to 1000 μg/L, the maximum cumulative methane production decreased from 163.5 ± 2.6 mL/g VS to 150.9 ± 4.5 mL/g VS. In particular, roxithromycin inhibited the acidogenesis and methanogenesis in WAS anaerobic digestion, leading to the decreased methane production. The methanogenic archaea in the studied system mainly belonged to the genera of Methanoseata, Candidatus Methanofastidiosum and Methanolinea and their relative abundances also decreased with roxithromycin addition. The analysis of antibiotic resistance genes (ARGs) in the digested sludge indicated that the abundances of most ARGs detected in this study were increased with roxithromycin exposure, suggesting the potential of growing antibiotic resistance, which was probably caused by enhancing the effect of esterases, methylases and phosphorylases. This work reveals how roxithromycin affects the WAS anaerobic digestion and the change of ARGs in the anaerobic digestion with roxithromycin exposure, and provides useful information for practical operation.
大环内酯类抗生素罗红霉素作为一种新兴污染物，广泛存在于各种水生环境中，尤其是在废水处理系统中，对其中涉及的微生物会产生显著影响。本研究全面考察了罗红霉素冲击负荷对剩余活性污泥（WAS）厌氧消化的影响。生物化学甲烷潜能测试表明，罗红霉素显著抑制了 WAS 厌氧消化的甲烷生成。随着罗红霉素剂量从 0 增加到 1000μg/L，最大累积甲烷产量从 163.5±2.6mL/gVS 降至 150.9±4.5mL/gVS。特别是，罗红霉素抑制了 WAS 厌氧消化中的产酸和产甲烷作用，导致甲烷生成减少。研究系统中的产甲烷古菌主要属于 Methanoseata、Candidatus Methanofastidiosum 和 Methanolinea 属，其相对丰度也随着罗红霉素的添加而降低。消化污泥中抗生素抗性基因（ARGs）的分析表明，本研究中检测到的大多数 ARGs 的丰度随着罗红霉素的暴露而增加，表明存在抗生素抗性增长的潜力，这可能是由于酯酶、甲基酶和磷酸酶的作用增强所致。这项工作揭示了罗红霉素如何影响 WAS 厌氧消化以及在罗红霉素暴露下厌氧消化中 ARGs 的变化，并为实际操作提供了有用的信息。
