Microbial community of four nitrobacteria enrichments by high-throughput sequencing

Abstract:

[Objective] To analyze and compare the microbial community composition and structure of four nitrobacteria enrichments i.e A: enrichment using ammonium as nitrogen source in freshwater, B: enrichment using nitrite as nitrogen source in freshwater, C: enrichment using ammonium as nitrogen source in freshwater at low temperature and D: enrichment using nitrite as nitrogen source in seawater. [Methods] The DNA of microbes in four samples were extracted, then high-throughput sequencing technology was used to analyze bacterial communities, abundance and diversity. [Results] The results showed that the microbial community was dominated by phylum Proteobacteria. β-Proteobacteria and γ-Proteobacteria were the dominant bacteria of sample A, B and C, while γ-Proteobacteria, δ-Proteobacteria and Bacilli were the dominant bacteria of sample D. The dominant genera were different in four nitrobacteria enrichments, the dominant species of sample A was Nitrosomonas (24.56%), the dominant species of sample B was Streptomyces lushanensis (7.15%), the dominant species of sample C were Bacteriovorax stolpii (19.36%) and Nocardioides daecheongensis (19.35%), while the dominant species of sample D were Acidovorax anthurii (13.6%) and Caulobacter segnis (11.5%). 7 groups of nitrobacteria were detected in 4 samples, the majority genus of sample A, B and D was Nitrosomonas, accounting for 24.56%, 4.94% and 0.63% relative abundance, respectively; Nitrospirillum (0.69%) and Nitrospira (0.69%) were the dominant bacteria of sample C. Apart from that, there were beneficial bacteria and pathogens detected in samples, such as Alcanivorax, Bradyrhizobium, Vibrio and Burkholderia etc. [Conclusion] Bacterial diversity, the group of nitrifying bacteria which played a main role in nitrification and other microbial groups related to environmental cycling or special physiological characteristics laid a foundation for its practical application.