National Engineering Laboratory for Industrial Wastewater Treatment, School of Resources and Environmental Engineering , East China University of Science and Technology , Shanghai 200237 , China.
Department of Environmental Engineering, College of Environmental and Resource Science , Zhejiang University , Hangzhou 310027 , China.
Environ Sci Technol. 2018 Sep 18;52(18):10665-10672. doi: 10.1021/acs.est.8b02314. Epub 2018 Sep 10.
Anaerobic ammonium oxidation (anammox) combined with partial-denitrification (NO → NO) is an innovative process for the simultaneous removal of ammonia and nitrate from wastewaters. An efficient method for the selection of partial denitrifying community, which relies on increasing influent salinity, is described. Using this method, a denitratating community was enriched, which showed a nitrite accumulation efficiency higher than 75% as well as a high nitrate conversion efficiency. Community analysis using 16S rDNA indicated that Halomonas became the dominant genus as salinity increased. Metagenomic analysis revealed that there was not a significant difference in reads mapping to downstream denitrification genes in a comparison of samples from cultures with 5% salinity to those without salinity. The majority of the reads mapping to the genes encoding dissimilatory nitrate and nitrite reductases nar and nirS came from Halomonas under high salinity conditions. Two metagenome-assembled genomes taxonomically assigned to Halomonas were obtained, one of which accounted for ∼35% of the reads under high salinity conditions. Both genomes harbored the genes for the complete denitrification pathway. These results indicate progressive onset denitrifiers, a phenotype where nitrite reduction only occurs after nitrate exhaustion, could be successfully enriched with increasing salinity. Progressive onset denitrifiers may be more widespread in natural and artificial habitats than anticipated and are shown here to be valuable for nitrogen mitigating processes.
厌氧氨氧化（anammox）与部分反硝化（NO→NO）相结合是一种从废水中同时去除氨和硝酸盐的创新工艺。本文描述了一种依赖于提高进水盐度来选择部分反硝化群落的有效方法。使用这种方法，富集了具有硝态氮转化效率高、亚硝态氮积累效率高于 75%的脱氮群落。16S rDNA 群落分析表明，随着盐度的增加，盐单胞菌属成为优势属。宏基因组分析表明，在盐度为 5%的培养物与无盐度的培养物的样品之间，下游反硝化基因的读映射没有显著差异。在高盐条件下，大多数映射到异化硝酸盐和亚硝酸盐还原酶 nar 和 nirS 编码基因的读都来自盐单胞菌属。获得了两个分类学上归属于盐单胞菌属的宏基因组组装基因组，其中一个在高盐条件下占读的约 35%。两个基因组都含有完整反硝化途径的基因。这些结果表明，随着盐度的增加，可能成功富集了具有渐进式硝酸盐还原能力的反硝化菌，即只有在硝酸盐耗尽后才发生亚硝酸盐还原的表型。渐进式硝酸盐还原菌可能比预期的更广泛地存在于自然和人工生境中，并且在这里被证明对氮素减排过程很有价值。
