Aerobic denitrifying bacteria that produce low levels of nitrous oxide
Aerobic denitrifying bacteria that produce low levels of nitrous oxide
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DOI：
10.1128/aem.69.6.3152-3157.2003
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发表时间：
2003-06-01
影响因子：
4.4
通讯作者：
Shoun, H
中科院分区：
文献类型：
--
作者：
Takaya, N;Catalan-Sakairi, MAB;Shoun, H
大多数反硝化菌在好氧条件下会产生一氧化二氮(N2O)而不是氮素(N-2)。我们分离并鉴定了在好氧条件下产生低水平NO的新型好氧反硝化菌。我们对其中两个菌株TR2和K50的反硝化活性进行了分批和连续培养的监测。在溶解氧(O-2)浓度分别为39和38摩尔升(-1)的条件下，两株菌株在540 nm(-1)处分别以0.9和0.03mumol min(-1)的光密度单位将硝酸盐还原为N-2。在相同的DO水平下，典型的反硝化假单胞菌Stutzeri和前述的好氧反硝化菌Paracoccus denitriicans不产生N-2，但比TR2和K50产生的N2O多10倍以上。这些菌株对NO_3~-进行反硝化，同时消耗O~-2。这些结果表明，菌株TR2和K50是好氧反硝化菌。这两个分离物在分类上被归入变形杆菌纲的Beta亚类，并被鉴定为P.stutzeri TR2和Pseudomonas sp。菌株K50。这些菌株将有助于进一步研究反硝化细菌调节N2O排放、单级脱氮过程以及微生物向生态系统排放N2O的机制。
Most denitrifiers produce nitrous oxide (N2O) instead of dinitrogen (N-2) under aerobic conditions. We isolated and characterized novel aerobic denitrifiers that produce low levels of NO under aerobic conditions. We monitored the denitrification activities of two of the isolates, strains TR2 and K50, in batch and continuous cultures. Both strains reduced nitrate (NO3-) to N-2 at rates of 0.9 and 0.03 mumol min(-1) unit of optical density at 540 nm(-1) at dissolved oxygen (O-2) (DO) concentrations of 39 and 38 mumol liter(-1), respectively. At the same DO level, the typical denitrifier Pseudomonas stutzeri and the previously described aerobic denitrifier Paracoccus denitrificans did not produce N-2 but evolved more than 10-fold more N2O than strains TR2 and K50 evolved. The isolates denitrified NO3- with concomitant consumption of O-2. These results indicated that strains TR2 and K50 are aerobic denitrifiers. These two isolates were taxonomically placed in the beta subclass of the class Proteobacteria and were identified as P. stutzeri TR2 and Pseudomonas sp. strain K50. These strains should be useful for future investigations of the mechanisms of denitrifying bacteria that regulate N2O emission, the single-stage process for nitrogen removal, and microbial N2O emission into the ecosystem.