Potential of Aerobic Denitrification by Pseudomonas stutzeri TR2 To Reduce Nitrous Oxide Emissions from Wastewater Treatment Plants
Potential of Aerobic Denitrification by Pseudomonas stutzeri TR2 To Reduce Nitrous Oxide Emissions from Wastewater Treatment Plants
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DOI：
10.1128/aem.01983-09
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发表时间：
2010-07-01
影响因子：
4.4
通讯作者：
Shoun, Hirofumi
中科院分区：
文献类型：
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作者：
Miyahara, Morio;Kim, Sang-Wan;Shoun, Hirofumi
与迄今为止研究的大多数发酵剂相反，施氏假单胞菌TR2即使在有氧条件下也会产生低水平的一氧化二氮（N2O）。我们比较了菌株TR2的反硝化活性与那些来自猪场废水的人工培养基中的各种微生物。菌株TR2具有较强的反硝化活性，在所有条件下都几乎不产生N2O。该菌株在厌氧条件下的生长速度与好氧条件下的生长速度相当，与其他厌氧条件下较低的生长速度形成鲜明对比。菌株TR2对有毒的亚硝酸盐具有耐受性，甚至可以将其作为良好的反硝化底物。当亚硝酸盐和N2O同时存在时，TR2菌株优先还原N2O而不是亚硝酸盐作为反硝化底物。该细菌菌株通过表达细胞色素cd（1）亚硝酸还原酶（NiR）（nirS）和一氧化二氮还原酶（NoS）（nosZ）的反硝化基因而能够容易地适应硝化条件。有趣的是，nosZ的组成型表达，即使在非发酵，有氧条件下，与我们的发现，TR2菌株喜欢N2O亚硝酸盐。TR2菌株的反硝化特性与那些特性良好的反硝化菌形成鲜明对比。这些结果表明，一些细菌物种，如菌株TR2，已采取了一种生存策略，通过优先反硝化氧呼吸。该细菌还被证明在应用于污水处理领域时具有减少N2O排放的潜力。
In contrast to most denitrifiers studied so far, Pseudomonas stutzeri TR2 produces low levels of nitrous oxide (N2O) even under aerobic conditions. We compared the denitrification activity of strain TR2 with those of various denitrifiers in an artificial medium that was derived from piggery wastewater. Strain TR2 exhibited strong denitrification activity and produced little N2O under all conditions tested. Its growth rate under denitrifying conditions was near comparable to that under aerobic conditions, showing a sharp contrast to the lower growth rates of other denitrifiers under denitrifying conditions. Strain TR2 was tolerant to toxic nitrite, even utilizing it as a good denitrification substrate. When both nitrite and N2O were present, strain TR2 reduced N2O in preference to nitrite as the denitrification substrate. This bacterial strain was readily able to adapt to denitrifying conditions by expressing the denitrification genes for cytochrome cd(1) nitrite reductase (NiR) (nirS) and nitrous oxide reductase (NoS) (nosZ). Interestingly, nosZ was constitutively expressed even under nondenitrifying, aerobic conditions, consistent with our finding that strain TR2 preferred N2O to nitrite. These properties of strain TR2 concerning denitrification are in sharp contrast to those of well-characterized denitrifiers. These results demonstrate that some bacterial species, such as strain TR2, have adopted a strategy for survival by preferring denitrification to oxygen respiration. The bacterium was also shown to contain the potential to reduce N2O emissions when applied to sewage disposal fields.