一株兼性氧化亚氮还原菌的还原N2O能力

Capability of N2O reduction of a facultative N2O reducer

摘要:

[目的]从水稻土中分离筛选出一株兼性氧化亚氮还原菌，并探索其在不同条件下还原N₂O的能力，为减少温室气体N₂O的排放提供重要依据。[方法]通过微生物富集培养分离技术从水稻土中分离得到纯菌；利用nosZ基因和16S rRNA的测序分析鉴定菌株；通过测定菌株在不同条件下N₂O的还原量，分析该菌株还原N₂O的能力及调控因子。[结果]经鉴定，该菌株含有nosZ基因，属于假单胞菌属，在温度30℃、厌氧条件下还原N₂O速率高达0.0219 μmol/min以上，改变不同温度和氧气浓度后其能力相对减弱，但仍具备较强的还原N₂O作用。[结论]从水稻土中分离筛选得到的兼性氧化亚氮还原菌为假单胞菌，它在不同环境条件下都具备较强的还原N₂O能力，该菌株可能为减少土壤N₂O排放提供新途径，对保障生态环境安全具有重要的应用价值。

Abstract:

[Objective] A nitrous oxide reducing bacterium (DJ7) was isolated from paddy soil and its ability to reduce N₂O was detected under different incubation conditions. Aiming to understand the mechanisms of N₂O reduction and supply theoretical basis for regulation of N₂O emission. [Methods] The strain was isolated by microbial enrichment culture and identified by homogeneous analysis of its sequences of nosZ and 16S rRNA gene with the database of NCBI. The abilities of N₂O-reducing of DJ7 at different temperatures and O₂ concentrations were determined by measuring the amount of N₂O reduction through GC. [Results] The strain was characterized as Pseudomonas and contained nosZ gene, its N₂O reduction rate was more than 0.0219 μmol/min under anaerobic at 30℃. Although the increase of air O₂ concentration and shifts of incubation temperature at either direction resulted decreases of the capability of N₂O reduction, it maintained a certain ability in N₂O reduction. [Conclusion] The strain is an active facultative N₂O reducer belonging to Pseudomonas and possesses strong ability to reduce N₂O, especially under anaerobic condition. This strain may provide a new idea to alleviate the N₂O issue and play an active role in the ecological environment.