Is nitrous oxide, a greenhouse gas, generated by anammox process?

2016 Fiscal Year Final Research Report

• Project/Area Number: 26450105
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied microbiology
• Research Institution: Sojo University
• Principal Investigator: FUJII Takao 崇城大学, 生物生命学部, 教授 (80165331)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 嫌気性アンモニア酸化 / anammox / ヘムタンパク質 / ヒドラジン合成 / 温暖化ガス生成 / 一酸化二窒素生成 / ヒドラジン合成酵素 / NaxLS

Outline of Final Research Achievements

It was investigated whether nitrous oxide, a greenhouse gas, was generated by anaerobic ammonium oxidation. Experimental data showed the facts described below. Nitrous oxide was not ordinarily generated as a byproduct in the cases using hydrazine-synthesizing enzyme plus NaxLS (HZS+NaxLS), nitrite reductase, and hydroxylamine oxidoreductase. Furthermore, the structure analyses of HZS + NaxLS demonstrated that the two proteins formed a complex (HZS-NaxLS), which enabled rapid intermolecular electron transfer between NaxLS and an active site of HZS. The rapid electron transfer might cause HZS-NaxLS catalyzing denitrification without generation nitrous oxide.　In an anammox reactor, the amounts of nitrous oxide gas formed did not correlate with those of nitrogen gas generated from anammox bacteria. Taken together, it was confirmed that anammox hardly generated nitrous oxide as a byproduct.

Free Research Field

微生物生化学