Anaerobic sludge
Genomic DNA was fragmented to an average size of approximately 350 bp using a Covaris M220 ultrasonicator (Gene Company Limited, China) for paired-end library preparation. A paired-end library was built using the NEXTFLEX Rapid DNA-Seq (Bioo Scientific, Austin, TX, USA). Paired-end sequencing was carried out on the Illumina NovaSeq X Plus (Illumina Inc., San Diego, CA, USA) at Majorbio Bio-Pharm Technology Co., Ltd. (Shanghai, China). The NovaSeq X Series 25B Reagent Kit was used for the sequencing, following the manufacturer's guidelines