title: 16S metabarcoding:PCR negative control
design: Two-step PCR approach. First-round PCR was performed with the 16S primers ewD/ewE tailed with the Illumina sequencing primer sequences. The purified amplicons from this first reaction were dual-indexed in a second-round PCR. Finished libraries were purified with magnetic beads and pooled in equimolar amounts for Illumina MiSeq PE300 sequencing.