mock
DNA was extracted using the DNeasy Power Soil kit (QIAGEN, Hilden, Germany) and its concentration and purity measured using Qubit dsDNA HS Assay Kit (Thermo Fisher Scientific) and BioDrop LITE nano-spectrophotometer (Biodrop, UK), respectively. All the samples were stored at -20C . DNA was sequenced commercially using the platform Illumina NovaSeq 6000, and the libraries were prepared by a two-step PCR employing the Nextera technology targeting the 16S rRNA genes V3 and V4 hypervariable regions using the primers 357F (5-CCTACGGGNGGCWGCAG-3) and 805R (5-GACTACHVGGGTATCTAATCC-3). A mock community consisting of 15 bacterial strains was included as a positive control.