Real-time monitoring of ammonia-oxidizing activity in a nitrifying biofilm by amoA mRNA analysis

Y. Aoi, Y. Shiramasa, Satoshi Tsuneda, A. Hirata, A. Kitayama, T. Nagamune

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    Ammonia monooxygenase encoding mRNA (amoA mRNA) transcription in the wastewater treatment process was investigated using reverse transcription PCR (RT-PCR) as the model indicating specific function and activity in nitrifying processes. The dynamic response of amoA mRNA transcription and ammonia-oxidizing activity to the change of environmental conditions such as pH and concentration of ammonia was examined to determine the inductive factor and the inhibitor for amoA mRNA expression. Furthermore, we semiquantitatively investigated the response of amoA mRNA transcription to the pH fluctuation in a continuous fed nitrifying reactor. As a result, amoA mRNA oriented analysis enabled real-time assay of ammonia-oxidizing activity within 2 h as a response time. In contrast, rRNA and amoA encoding DNA were constantly detected at almost the same amount throughout the experiment. mRNA transcription was regulated by the many environmental conditions: ammonia seems to be one of the strong inducers for transcription of amoA mRNA, whereas low pH seems to be a strong inhibitor. These factors simultaneously affected the mRNA transcription and enzymatic activity leading to the complex phenomena of ammonia-oxidizing activity and amoA mRNA transcription in the continuous feeding reactors.

    Original languageEnglish
    Pages (from-to)439-442
    Number of pages4
    JournalWater Science and Technology
    Issue number1-2
    Publication statusPublished - 2002



    • Ammonia-oxidizing activity
    • amoA mRNA
    • Biofilm
    • Nitrification process
    • RT-PCR

    ASJC Scopus subject areas

    • Water Science and Technology

    Cite this

    Aoi, Y., Shiramasa, Y., Tsuneda, S., Hirata, A., Kitayama, A., & Nagamune, T. (2002). Real-time monitoring of ammonia-oxidizing activity in a nitrifying biofilm by amoA mRNA analysis. Water Science and Technology, 46(1-2), 439-442.