Abstract

A novel and efficient facultative anaerobic denitrifying bacterium was isolated and identified as Pseudomonas citronellolis WXP-4. The strain WXP-4 could achieve 100% nitrate and nitrite removal efficiency utilizing sodium succinate as a carbon source, C/N ratio 7, pH 7.0, and temperature 40 °C under both aerobic and anaerobic conditions. The bacterium could tolerate a wide range of NO₃⁻–N concentrations from 100 to 1000 mg/L with a maximum nitrogen removal rate of 32.05 mg/(L h). An interesting phenomenon was found that no N₂O emission occurred during the denitrifying process under anaerobic conditions, while there was 0.06 mg/L under aerobic conditions. This phenomenon had been confirmed by fluorescence quantitative PCR and the results showed that the relative abundance of nosZ gene increased by 17-fold based on the ratio of anaerobic to aerobic, and thus, nosZ gene could encode more nitrous oxide reductase to accelerate the conversion of N₂O under anaerobic conditions. Moreover, the narG, nirK, and norB genes were also identified in the denitrifying pathway of the strain WXP-4. This investigation has demonstrated enormous potential for the future application in wastewater treatment systems.

Graphic abstract

中文翻译：

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一种新近分离和快速反硝化的香茅假单胞菌WXP-4：好氧和厌氧条件下N 2 O排放的差异

摘要

分离出一种新型的高效兼性厌氧反硝化细菌，并将其鉴定为香茅假单胞菌WXP-4。在有氧和无氧条件下，利用琥珀酸钠作为碳源，C / N比7，pH 7.0和温度40°C，菌株WXP-4可以实现100％的硝酸盐和亚硝酸盐去除效率。该细菌可以耐受100至1000 mg / L的宽范围的NO ₃ ^-- N浓度，最大脱氮率为32.05 mg /（L h）。发现一个有趣的现象是没有N ₂在厌氧条件下，反硝化过程中会产生O排放，而在好氧条件下，则为0.06 mg / L。荧光定量PCR证实了这一现象，结果表明，nosZ基因的相对丰度基于厌氧与好氧的比率增加了17倍，因此，nosZ基因可以编码更多的一氧化二氮还原酶，从而促进NsZ的转化。 N ₂ O在厌氧条件下。此外，还在菌株WXP-4的反硝化途径中鉴定了narG，nirK和norB基因。这项研究证明了未来在废水处理系统中的巨大应用潜力。

图形摘要