Amplicon sequencing of extraction control 2. Sequencing was performed as described in https://doi.org/10.3389/fmicb.2021.669776. {primers: GTGYCAGCMGCCGCGGTAA + GGACTACNVGGGTWTCTAAT, nucleic acid: DNA, flow cell identifier: KNYD6, barcoding: UDB-H12, plate-position: 3 G4, barcodes: TATGGAGCTAGT + TATGGCCAAACC}.