Quantification of the contribution of each pathway in N2O production from nitrifying bacteria by using a dual-labeled tracer technique

• Project/Area Number: 24710012
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Environmental dynamic analysis
• Research Institution: Chuo University
• Principal Investigator: KATSUYAMA Chie 中央大学, 理工学部, 助教 (10580061)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Project Status: Completed (Fiscal Year 2014)
• Budget Amount: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000); Fiscal Year 2013: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2012: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
• Keywords: 安定同位体トレーサー / アンモニア酸化細菌 / 亜酸化窒素 / 硝化 / 脱窒 / 窒素循環 / 温室効果ガス / ガスクロマトグラフィー質量分析計 / 好気性アンモニア酸化細菌 / 国際情報交換（USA、カナダ） / 硝化菌脱窒

Outline of Final Research Achievements

Ammonia-oxidizing bacteria (AOB) have been shown to produce nitrous oxide (N2O) from hydroxylamine (NH2OH) during ammonia oxidization and/or from nitrite (NO2-) during nitrifier denitrification under aerobic condition. The aim of this study is to determine which mechanisms are responsible for producing N2O by AOB species using a 15N and 18O tracer technique. (1) The fragmentation and the scrambling ratio of N2O were determined by GC/MS. (2) Cell suspension of Nitrosomonas strains formed hybrid N2O from NH2OH and NO2-. The dominant pathway in N2O production differed among Nitrosomonas strains under a condition, where they were allowed to grow optimally.

Research Products

• [Presentation] Dominant pathway in nitrous oxide production may differ among Nitrosomonas strains (2013)
  • Author(s): Chie Katsuyama, Keisuke Koba, Yuichi Suwa
  • Organizer: 3rd International Conference on Nitrification (ICoN3)
  • Place of Presentation: 中央大学（東京都）
• [Presentation] アンモニア酸化細菌の菌株により異なる亜酸化窒素の発生特性
  • Author(s): 勝山千恵，木庭啓介，諏訪裕一
  • Organizer: 第29回日本微生物生態学会大会
  • Place of Presentation: 鹿児島大学（鹿児島県）
• [Presentation] Evidence of hybrid N2O production from NH2OH and NO2- in cell suspension of oligotrophic ammonia-oxidizing bacterial strain Nitrosomonas sp. AL212 using a 15N and 18O tracer technique
  • Author(s): Chie Katsuyama, Keisuke Koba, Yuichi Suwa
  • Organizer: 第14回国際微生物生態学シンポジウム（ISME14）
  • Place of Presentation: コペンハーゲン市（デンマーク王国）
• [Presentation] 森林生態系の地下水帯における亜酸化窒素の発生と消費メカニズムの解明に向けた安定同位体の利用
  • Author(s): 勝山千恵, 大手信人, 加藤憲二, 諏訪裕一
  • Organizer: 第28回日本微生物生態学会大会
  • Place of Presentation: 豊橋技術科学大学（愛知県）