Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization, Sapporo, Hokkaido, Japan.
J Appl Microbiol. 2017 Dec;123(6):1498-1511. doi: 10.1111/jam.13603. Epub 2017 Nov 5.
To obtain insight into the complex behaviour of denitrifying and total bacterial groups during the nitrogen accumulation process in an ammonia-loaded biofiltration system.
Denitrifying and total bacterial communities in a laboratory-scale rockwool biofilter with intermittent water recirculation were analysed by using denaturing gradient gel electrophoresis targeting nosZ and metabarcoding sequencing of the 16S rRNA gene. Gene abundance was evaluated by quantitative PCR. The nosZ number increased from 6·59 × 10 to 3·33 × 10 copies per gram dry sample over the 436 days of operation, during which nitrogen mass balance errors increased to 39%. The nosZ sequences associated with the genera Castellaniella, Hyphomicrobium and Pseudomonas were detected. Metabarcoding sequencing analysis indicated that the proportions of the genera for which at least one denitrifying strain or species possessing nosZ had been characterized corresponded well to the nitrogen loss. In addition, the genus Nitrosococcus (γ-proteobacteria) increased its relative abundance at days 317 and 436.
The increased proportion of denitrifying bacteria in this ammonia-loaded biofiltration system could be related to the nitrogen loss.
These results will help to clarify the complex behaviour of nitrifiers and denitrifiers within ammonia-loaded biofiltration systems.
深入了解在氨负荷生物过滤系统中氮积累过程中反硝化菌和总细菌群的复杂行为。
通过使用针对 nosZ 的变性梯度凝胶电泳和 16S rRNA 基因的 metabarcoding 测序，分析了具有间歇水循环的实验室规模岩棉生物过滤器中的反硝化菌和总细菌群落。通过定量 PCR 评估基因丰度。nosZ 数量从运行的 436 天内的 6.59×10 增加到 3.33×10 拷贝/克干样品，在此期间，氮质量平衡误差增加到 39%。检测到与 Castellaniella、Hyphomicrobium 和 Pseudomonas 属相关的 nosZ 序列。 metabarcoding 测序分析表明，至少有一种具有 nosZ 的反硝化菌株或物种的属的比例与氮损失相对应。此外，Nitrosococcus 属（γ-变形菌）在第 317 天和第 436 天增加了其相对丰度。
在这个氨负荷生物过滤系统中，反硝化细菌的比例增加可能与氮损失有关。
这些结果将有助于阐明氨负荷生物过滤系统中硝化菌和反硝化菌的复杂行为。
