16S amplicon of microbial community : groundwater
sampling of microbial community on artificial substrate (clay beads) in groundwater, chemical lysis followed by extraction with PowerSoilPro kit of Qiagen, first amplification of a region of the rRNA 16S gene with 515F-Y/926R primer pair  (5-GTGYCAGCMGCCGCGGTAA-3/5-CCGYCAATTYMTTTRAGTTT-3), second amplification to add Illumina adaptors, sequencing 2*250 PE, Illumina MiSeq Reagent Kit v2