Biochemistry of aerobic ammonia-oxidizing archaea

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05805
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 38020:Applied microbiology-related
• Research Institution: Hokkaido University (2020-2021); Nagaoka National College of Technology (2019)
• Principal Investigator: oshiki mamoru 北海道大学, 工学研究院, 准教授 (90540865)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: アンモニア酸化古細菌 / AOA / 硝化 / 触媒分子 / タンパク質工学

Outline of Final Research Achievements

The present study aimed to examine the biochemistry of aerobic ammonium oxidizing archaea, Nitrososphaera viennensis. First, mass cultivation of Nitrososphaera viennensis using a membrane bioreactor has been developed, and the biomass cultivated in the reactor was subjected to protein isolation by liquid chromatography. Some enzymes were successfully isolated from N. viennensis culture and subsequently identified by MALDI-TOF/MS analysis. We also developed a heterologous protein expression system for N. viennensis protein, whereas a functional expression of those was quite challenging. Our achievements should advance the understanding of biochemistry of Nitrososphaera viennensis, while more efforts are definitely required to underpin the biochemistry of aerobic ammonia oxidation reaction.

Free Research Field

環境工学

Academic Significance and Societal Importance of the Research Achievements

好気性アンモニア酸化反応は地球上の窒素循環を担う大動脈であり、本反応のメカニズムを分子レベルで理解することは学術的にきわめて重要である。本研究では培養が困難であり、限られた知見しか得られていない好気性アンモニア酸化古細菌Nitrososphaera viennensisについて、触媒酵素を分離し、酵素レベルで反応を理解することを目指した。本研究では本細菌を高密度で大量培養する新規な培養技術の開発、タンパク質分離条件の検討、大腸菌を宿主としたタンパク質発現条件の検討を行っており、これらの成果は今後の生化学研究へのマイルストーンとなる成果といえる。