| 异养硝化/好氧反硝化菌的分离鉴定及其在不同培养条件下产N2O研究 |
| 摘要点击 1902 全文点击 1018 投稿时间：2008-08-28 修订日期：2008-11-13 |
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| 中文关键词 异养硝化/好氧反硝化 分离 N2O产生 |
| 英文关键词 heterotrophic nitrifier/aerobic denitrifier isolate N2O production |
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| 中文摘要 |
| 以乙酰胺为唯一碳氮源分离纯化出2株既能异养硝化又能好氧反硝化的菌株XM1和HX2，革兰氏阴性，分别为链状杆菌和球状菌.在富集培养基中，菌株HX2产N2O量为XM1的76倍；两菌株均能分别以葡萄糖、甘露醇、酒石酸钠为唯一碳源进行生长；也可分别以硝酸钠和硫酸铵为唯一氮源进行硝化和反硝化作用，但菌株XM1生长速率快于HX2，且有较多的NO-2积累.部分长度的16S rDNA序列分析表明，菌株XM1与HX2的序列与Pseudomonas sp.具有99%的相似性，定为假单胞菌属（Pseudomonas sp.）.两菌株27 d反接种培养实验结果表明，在添加外源N的条件下，HX2菌株更适合在30%的土壤水分（WFPS）条件下生长，N2O产生量为(36.01±2.48) ng/g，为60% WFPS条件下N2O产生量的1.9倍；而菌株HX1则适合在60%的水分条件下生长，在该条件下几乎不产生N2O. |
| 英文摘要 |
| Soil microorganisms are important sources of N2O for the atmosphere. Peak emissions of N2O are often observed after wetting of soil. The simultaneous heterotrophic nitrifying and aerobic denitrifying bacteria with respect to N2O emission were studied to obtain more information about the microbiological aspects of peak emissions. Using acetamide as the C and N source，two strains of nitrifying and denitrifying bacteria were isolated，coded as XM1 and HX2，respectively. XM1strain was Gram-negative chain-like bacilli，and the HX2 was Gram-negative cocci. In enrichment culture，N2O production of HX2 was 76 times more than XM1. Two strains could grow with glucose，mannitol or sodium tartrate as sole carbon source，respectively. They could nitrify with sodium nitrate or denitrify with ammonium sulfate as unique nitrogen source，and produce intermediate product nitrite. XM1strain growth velocity and nitrite formation were obviously higher than HX2. The phylogentic analysis based on partial 16S rDNA showed that two isolated strains were the closest relative of Pseudomonas sp.99% sequence similarity. Under different WFPS (water-filled-pore-space) conditions，the aerobic autoclaved soil incubation trial showed that，HX2 strain was suitable for growing in 30% WFPS，and N2O production was (36.01±2.48) ng/g which was 1.9 times than that in 60% WFPS. But XM1 was suitable for growing in 60% WFPS and almost had no N2O production. To investigate the nitrifying and denitrifying mechanisms of heterotrophic nitrifiers/aerobic denitrifiers should be useful for mastering the mitigation way of soil N2O emission in future. |
