摘要
      在序批式反应器（SBR）中评价了磺胺甲恶唑（SMX）对短程硝化反硝化（SCND）和抗生素抗性基因（ARGs）的影响机制。在0.0–1.2 mg/L SMX下，NH4+-N和总无机氮（TIN）的去除率分别达到95.7%和93.0%以上，而2.0 mg/L SMX使其去除率分别下降到53.5%和55.2%。SMX与微生物呈正相关，从而改变了微生物组成，导致优势微生物从牛仔单胞菌转变为弧菌，并出现更多的抗生素耐药性细菌（ARB）。SMX剂量显著抑制氨氧化细菌（AOB）硝化单胞菌，但使反硝化细菌（DNB）富集和多样化。2.0mg/L SMX导致异养硝化-好氧反硝化（HNAD）作为一种脱氮途径的出现，并通过富集SOAD细菌（Candidatus_Thiobios，Sedimicicola）加强了硫化物氧化自养反硝化（SOAD）过程。宏基因组分析显示，2.0mg/L SMX通过在遗传水平上减少硝化相关基因（amoABC，hao）来降低NH4+-N的去除。与0.0mg/L SMX相比，2.0mg/L SMX通过抑制碳源代谢相关基因（如ACSS、sucC、mdh）显著抑制异养反硝化过程的电子供应，但通过增强硫化物氧化相关基因aprA和aprB刺激自养反硝化的电子产生。此外，2.0mg/L的SMX诱导了更高的抗生素抗性基因（ARGs）多样性和相对百分比，但几乎不影响ARGs的潜在传播能力，这表明在SMX处理海水养殖废水的情况下，SCND是一个很有前途的控制ARGs传播的系统。
Abstract
The influential mechanism of sulfamethoxazole (SMX) on short-cut nitrification and denitrification (SCND) and antibiotic resistance genes (ARGs) was evaluated in a sequencing batch reactor (SBR). Excellent removal for NH4+-N and total inorganic nitrogen (TIN) was realized with above 95.7 and 93.0 % under 0.0–1.2 mg/L SMX, while 2.0 mg/L SMX induced the deterioration of their removal to 53.5 and 55.2 %, respectively. SMX altered the microbial composition by showing positive correlation to microbes, resulting in the dominant microorganisms changing from Denitromonas to Vibrio and occurrence of more antibiotic resistance bacteria (ARB). SMX dosage suppressed significantly ammonia oxidizing bacteria (AOB) Nitrosomonas, but enriched and diversified the denitrifying bacteria (DNB). 2.0 mg/L SMX led to the emergence of heterotrophic nitrification-aerobic denitrification (HNAD) as a nitrogen removal pathway and strengthened the sulfide-oxidizing autotrophic denitrification (SOAD) process by enrichment of SOAD bacteria (Candidatus_Thiobios, Sedimenticola). Metagenomic analysis revealed that 2.0 mg/L SMX decreased the NH4+-N removal by reducing nitrification related genes (amoABC, hao) at genetic level. Compared with 0.0 mg/L SMX, 2.0 mg/L SMX significantly inhibited the electron supply for heterotrophic denitrifying process by restraining the carbon source metabolism related genes (such as ACSS, sucC, mdh), but stimulated the electron generation for autotrophic denitrification by enhancing sulfide oxidation related genes aprA and aprB. Moreover, 2.0 mg/L SMX induced higher diversity and relative percentage of antibiotic resistance genes (ARGs) but barely affected the potential ability of dissemination of ARGs, revealing SCND was a promising system for controlling transmission of ARGs under SMX treating mariculture wastewater.

https://www.sciencedirect.com/science/article/abs/pii/S1385894722059976