sequences of * gene
Sludge samples were collected on day 0 (S_0, inoculated activated sludge) and S_1, from R1; S_2, from R2; S_3, from R3;S_4, from R4;S_5, from R5), and total genomic DNA was extracted using the FastDNA SPIN Kit for Soil (MP Biomedicals, USA). The DNA extract was fragmented to a mean size of around 400 bp using Covaris M220 (Gene Company Limited, China) for construction of paired-end library. Adapters were bound to the Blunt_x0002_end of fragments and paired-end sequencing of the purified meta_x0002_genomic DNA was performed on Illumina NovaSeq 6000 platform (Illumina Inc., USA) at Majorbio Bio-Pharm Technology Co., Ltd. (Shanghai, China) using NovaSeq Reagent Kits. The paired-end Illumina reads were trimmed of adaptors, and low-quality reads (length < 20 or existing N bases) were removed by fastp (http s://github.com/OpenGene/fastp, version 0.20.0). T