Optimization of a method for diversity analysis of anammox bacteria using high-throughput sequencing of 16S rRNA gene amplicon

High-throughput sequencing of 16S rRNA amplicons is an effective method for diversity analysis of anammox bacteria. However, the corresponding taxonomic database and suitable cut-off value are unavailable for processing high-throughput sequencing data. This study is the first to construct a taxonomic database, comprising 17 sequences of enriched anammox strains (regarded as seed sequences) and 2925 uncultured sequences from environmental samples. Moreover, a suitable cut-off value was determined based on pairwise evolutionary distances between the 16S rRNA gene sequences of the 17 identified species and diversity indexes of community in the taxonomic database. Furthermore, the proposed method was validated with multiple environmental samples. In summary, the taxonomic database and proposed cut-off value targeting the 16S rRNA gene presented in this study can be effectively employed to explore the diversity of anammox bacteria.