Metagenomic of urban water
The DNA extracts were fragmented into sizes of 400 bp using a Covaris M220 (Cene Company Limited, China) for the preparation of paired-end library construction. Subsequently the NEXT-flex Rapid DNA-Seq Kit (Bioo Scientific, Austin, TX, USA) was used to creat library. The paired-end sequencing was carried out by the Illumina NovaSeq platform (Illumina Inc., San Diego, CA, USA).