design: Amplicon sequencing of DNA extraction negative control 1. Sequencing was performed as described in https://doi.org/10.3389/fmicb.2021.669776. {primers: GTGYCAGCMGCCGCGGTAA + GGACTACNVGGGTWTCTAAT, nucleic acid: DNA, flow cell identifier: JBJYD, barcoding: UDB-H12, plate-position: 1 D10, barcodes: CACCCACGTTGA + CACGAGCTACTC}.