Ferrous and manganese ions, as essential elements, significantly affect the synthesis of Haem-C, which participates in the energy metabolism and proliferation of anammox bacteria. In this study, two identical sequenci...Ferrous and manganese ions, as essential elements, significantly affect the synthesis of Haem-C, which participates in the energy metabolism and proliferation of anammox bacteria. In this study, two identical sequencing batch biofilm reactors were used to investigate the effects of ferrous and manganese ions on nitrogen removal efficiency and the potential of metal ions serving as electron donor/acceptors in the anammox process. Fluorescence in situ hybridization analysis was applied to investigate the microbial growth. Results showed that the nitrogen removal increased at high concentrations of Fe2＋ and Mn2＋ and the maximum removal efficiency was nearly 95% at Fe2＋ 0.08 mmol/L and Mn2＋ 0.05 mmol/L, which is nearly 15% and 8% higher than at the lowest Fe2＋ and Mn2＋ concentrations （0.04 and 0.0125 mmol/L）. The stabilities of the anammox reactor and the anammox bacterial growth were also enhanced with the elevated Fe2＋ and Mn2＋ concentrations. The Fe2＋ and Mn2＋were consumed by anammox bacteria along with the removal of ammonia and nitrite. Stoichiometry analysis showed Fe2＋ could serve as an electron donor for NO3-N in the anammox process. Nitrate could be reduced with Fe2＋ serving as the electron donor in the anammox system, which causes the value of NO^-N/NH4-N to decrease with the increasing of N-removal efficiency.展开更多
Though there are many literatures studying the effects of iron on anammox process,these studies only focus on the reactor performance and/or the microbial community changes,the detailed effects and mechanisms of Fe(II...Though there are many literatures studying the effects of iron on anammox process,these studies only focus on the reactor performance and/or the microbial community changes,the detailed effects and mechanisms of Fe(II)on anammox bacterial activity and physiology have not been explored.In this study,four Fe(II)concentrations(0.03,0.09,0.12 and 0.75 mmol/L)were employed into the enriched anammox culture.The enhancement and inhibition effects of Fe(II)on anammox process and bacterial physiology were investigated.It was discovered that the anammox process and bacterial growth were enhanced by 0.09 and 0.12 mmol/L Fe(II),in which the 0.12 mmol/L Fe(II)had advantage in stimulating the total anammox activity and bacterial abundance,while 0.09 mmol/L Fe(II)enhanced the relative anammox activity better.The anammox activity could be inhibited by 0.75 mmol/L Fe(II)immediately,while the inhibition was recoverable.Both 0.09 and 0.12 mmol/L Fe(II)induced more genes being expressed,while didn’t show a stimulation on the relative expression level of functional genes.And anammox bacteria showed a stress response to detoxify the Fe inhibition once inhibited by 0.75 mmol/L Fe(II).This study provides more information about physiologic response of anammox bacteria to external influence(enhancement and inhibition),and may also instruct the future application of anammox process in treating various sources of wastewater(containing external disturbances such as heavy metals)and/or different treatment strategies(e.g.from side-stream to main-stream).展开更多
基金supported by the National Natural Science Foundation of China(No.21177033)
文摘Ferrous and manganese ions, as essential elements, significantly affect the synthesis of Haem-C, which participates in the energy metabolism and proliferation of anammox bacteria. In this study, two identical sequencing batch biofilm reactors were used to investigate the effects of ferrous and manganese ions on nitrogen removal efficiency and the potential of metal ions serving as electron donor/acceptors in the anammox process. Fluorescence in situ hybridization analysis was applied to investigate the microbial growth. Results showed that the nitrogen removal increased at high concentrations of Fe2＋ and Mn2＋ and the maximum removal efficiency was nearly 95% at Fe2＋ 0.08 mmol/L and Mn2＋ 0.05 mmol/L, which is nearly 15% and 8% higher than at the lowest Fe2＋ and Mn2＋ concentrations （0.04 and 0.0125 mmol/L）. The stabilities of the anammox reactor and the anammox bacterial growth were also enhanced with the elevated Fe2＋ and Mn2＋ concentrations. The Fe2＋ and Mn2＋were consumed by anammox bacteria along with the removal of ammonia and nitrite. Stoichiometry analysis showed Fe2＋ could serve as an electron donor for NO3-N in the anammox process. Nitrate could be reduced with Fe2＋ serving as the electron donor in the anammox system, which causes the value of NO^-N/NH4-N to decrease with the increasing of N-removal efficiency.
基金The authors also appreciate the funding support from Start-up Grant(SUG)Nanyang Technological University,Singapore(M4081483.030).
文摘Though there are many literatures studying the effects of iron on anammox process,these studies only focus on the reactor performance and/or the microbial community changes,the detailed effects and mechanisms of Fe(II)on anammox bacterial activity and physiology have not been explored.In this study,four Fe(II)concentrations(0.03,0.09,0.12 and 0.75 mmol/L)were employed into the enriched anammox culture.The enhancement and inhibition effects of Fe(II)on anammox process and bacterial physiology were investigated.It was discovered that the anammox process and bacterial growth were enhanced by 0.09 and 0.12 mmol/L Fe(II),in which the 0.12 mmol/L Fe(II)had advantage in stimulating the total anammox activity and bacterial abundance,while 0.09 mmol/L Fe(II)enhanced the relative anammox activity better.The anammox activity could be inhibited by 0.75 mmol/L Fe(II)immediately,while the inhibition was recoverable.Both 0.09 and 0.12 mmol/L Fe(II)induced more genes being expressed,while didn’t show a stimulation on the relative expression level of functional genes.And anammox bacteria showed a stress response to detoxify the Fe inhibition once inhibited by 0.75 mmol/L Fe(II).This study provides more information about physiologic response of anammox bacteria to external influence(enhancement and inhibition),and may also instruct the future application of anammox process in treating various sources of wastewater(containing external disturbances such as heavy metals)and/or different treatment strategies(e.g.from side-stream to main-stream).
