While emerging pharmaceutical contaminants are monitored in wastewater treatment and the environment, there is little information concerning their microbial metabolites. The transformation of diphenhydramine by microorganisms in anaerobic digester sludge was investigated using anaerobic cultures amended with 1 mM diphenhydramine as the sole carbon source. Complete transformation of the parent compound to a persistent metabolite occurred within 191 days. Using GC/MS analysis, the metabolite was identified as N-desmethyl diphenhydramine. Loss of the parent compound diphenhydramine followed a first order rate constant of 0.013 day⁻¹. There was no observed decrease in metabolite concentration even after a further 12 months of incubation, suggesting that the metabolite resists further degradation during wastewater treatment. Bacterial community diversity in the diphenhydramine transforming assay cultures showed enrichment in Comamonadaceae, Symbiobacteriaceae, Anaerolineaceae, and Prevotellaceae relative to unamended background controls. An anaerobic toxicity assay demonstrated that diphenhydramine has an inhibitory effect on both fermentative bacteria and methanogenic archaea in the wastewater community. In contrast, the metabolite N-desmethyl diphenhydramine partially suppressed methanogens but did not impact the fermenting community. To our knowledge, this is the first report of diphenhydramine metabolism by a bacterial community. The limited transformation of diphenhydramine by wastewater microorganisms indicates that N-desmethyl diphenhydramine will enter the environment along with unmetabolized diphenhydramine.

尽管在废水处理和环境中对新兴的药物污染物进行了监测，但有关其微生物代谢产物的信息却很少。使用1 mM苯海拉明作为唯一碳源的厌氧培养物，研究了微生物在厌氧消化池污泥中苯海拉明的转化情况。母体化合物完全转化为持久性代谢产物的时间为191天。使用GC / MS分析，将代谢物鉴定为N-去甲基苯海拉明。母体化合物苯海拉明的损失遵循0.013天^-1的一级速率常数。即使再培养12个月也没有观察到代谢物浓度的降低，这表明该代谢物在废水处理过程中仍能抵抗进一步的降解。在苯海拉明转化法文化细菌群落多样性表现出富集Comamonadaceae，Symbiobacteriaceae，Anaerolineaceae，并Prevotellaceae相对于未修改的背景控件。厌氧毒性试验表明，苯海拉明对废水社区的发酵细菌和产甲烷古菌都有抑制作用。相反，代谢物N-去甲基苯海拉明部分抑制了产甲烷菌，但没有影响发酵菌群。据我们所知，这是细菌群落中苯海拉明代谢的首次报道。废水微生物对苯海拉明的有限转化表明，N-去甲基苯海拉明将与未代谢的苯海拉明一起进入环境。