Relative Abundance of Nitrotoga spp. in a Biofilter of a Cold-Freshwater Aquaculture Plant Appears To Be Stimulated by Slightly Acidic pH
Relative Abundance of Nitrotoga spp. in a Biofilter of a Cold-Freshwater Aquaculture Plant Appears To Be Stimulated by Slightly Acidic pH
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DOI：
10.1128/aem.03163-15
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发表时间：
2016-01
影响因子：
4.4
通讯作者：
Jennifer Hüpeden;S. Wegen;Sandra Off;Sebastian Lücker;Yvonne Bedarf;H. Daims;C. Kühn;E. Spieck
中科院分区：
文献类型：
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作者：
Jennifer Hüpeden;S. Wegen;Sandra Off;Sebastian Lücker;Yvonne Bedarf;H. Daims;C. Kühn;E. Spieck
摘要再循环水产养殖系统（RAS）的运作对于维持水质以促进鱼类健康至关重要，其中一个关键过程是硝化作用。研究的RAS连接到虹鳟鱼生产系统，并在平均温度为13°C和pH 6.8的条件下运行。硝化生物膜的社区分析显示，Nitrospira和Nitrotoga的共存，它是假设一个稍微酸性的pH值与较低的温度相结合，有利于后者的生长。将标准培养方法向5.7至6.0的较低pH值的修改导致Nitrotoga sp.菌株HW 29的成功富集（99%纯度），其与Nitrotoga arctica的16S rRNA序列相似性为99.0%。参考培养物的Nitrospira defluvii和新的Nitrotoga sp. HW 29被用来确认这些亚硝酸盐氧化剂在不同的生态位的分化。Nitrotoga sp. HW 29的最适pH和温度分别为6.8和22°C，而Nitrospira defluvii在pH 7.3和32°C下显示出最高的亚硝酸盐氧化速率。我们在这里报告的发生Nitrotoga作为淡水养殖系统中的主要亚硝酸盐氧化细菌之一，并指出，微酸性的pH值，除了低于20°C的温度，可以作为这种微生物的选择性分离标准。
ABSTRACT The functioning of recirculation aquaculture systems (RAS) is essential to maintain water quality for fish health, and one crucial process here is nitrification. The investigated RAS was connected to a rainbow trout production system and operated at an average temperature of 13°C and pH 6.8. Community analyses of the nitrifying biofilm revealed a coexistence of Nitrospira and Nitrotoga, and it is hypothesized that a slightly acidic pH in combination with lower temperatures favors the growth of the latter. Modification of the standard cultivation approach toward lower pH values of 5.7 to 6.0 resulted in the successful enrichment (99% purity) of Nitrotoga sp. strain HW29, which had a 16S rRNA sequence similarity of 99.0% to Nitrotoga arctica. Reference cultures of Nitrospira defluvii and the novel Nitrotoga sp. HW29 were used to confirm differentiation of these nitrite oxidizers in distinct ecological niches. Nitrotoga sp. HW29 revealed pH and temperature optima of 6.8 and 22°C, respectively, whereas Nitrospira defluvii displayed the highest nitrite oxidation rate at pH 7.3 and 32°C. We report here the occurrence of Nitrotoga as one of the main nitrite-oxidizing bacteria in freshwater aquaculture systems and indicate that a slightly acidic pH, in addition to temperatures below 20°C, can be applied as a selective isolation criterion for this microorganism.