Experimental data: pharmaceuticals and personal-care products impact on nitrification

Nitrification is an important microbial process in wastewater, by which ammonia is oxidised to nitrate by two guilds of bacteria: Nitrosomonas and Nitrobacter. As a community, their synergistic interactions are important for the complete removal of ammonia from, not only wastewater, but also agricultural/terrestrial and freshwater/marine ecosystems. Decoupling the process by chemical inhibitors, e.g., pharmaceutical and personal care products, can disrupt the system’s to detoxify ammonia and complete the nitrogen cycle. In a series of microcosm experiments, enriched wastewater consortium of ammonia oxidising bacteria (Nitrosomonas sp.) and nitrite-oxidising bacteria (Nitrobacter spp.) were exposed to four antimicrobial agents (ampicillin, colistin, ofloxacin, and triclosan), insect repellent (N,N-diethyl-m-toluamide (DEET)) and a caffeine (a stimulant). Liquid cultures were exposed a range of toxicant concentrations, and the production of nitrite and nitrate were monitored (along with pH) over time. Allythiourea (ATU, 0.3 mg/L) was added as a selective inhibitor (control reaction). The aims of the project were: 1. to determine the extent that ammonia-oxidising performance can withstand the toxic effects of pharmaceuticals into wastewater 2. to develop a refined toxicological assessment tool for microbial communities.

硝化作用（Nitrification）是废水中重要的微生物过程，在此过程中氨通过两类细菌（亚硝化单胞菌属Nitrosomonas和硝化杆菌属Nitrobacter）氧化为硝酸盐。作为群落，它们的协同互作对于从废水、农业/陆地生态系统及淡水/海洋生态系统中彻底去除氨至关重要。通过化学抑制剂（如药品和个人护理产品）解耦该过程，会破坏系统对氨的解毒能力并干扰氮循环的完成。在一系列微宇宙实验中，富集的废水菌群（含氨氧化细菌亚硝化单胞菌属种Nitrosomonas sp.和亚硝酸盐氧化细菌硝化杆菌属种Nitrobacter spp.）暴露于四种抗菌剂（氨苄西林ampicillin、粘菌素colistin、氧氟沙星ofloxacin、三氯生triclosan）、驱虫剂N,N-二乙基间甲苯酰胺（DEET）及咖啡因（caffeine，一种兴奋剂）中。液体培养物暴露于不同浓度的毒物中，随时间监测亚硝酸盐和硝酸盐的生成（及pH值）。添加烯丙基硫脲（Allythiourea，ATU，浓度0.3 mg/L）作为选择性抑制剂（对照反应）。本项目目标为：1. 确定氨氧化性能抵御废水中药品毒性效应的能力范围；2. 开发针对微生物群落的精细化毒理学评估工具。