pH gradient soil year 2007
PCR was carried out using genomic DNA as template with modified 16S rRNA primers (which, in addition to targeting the bacterial 16S rRNA gene, also contain regions specific to Illumina paired-end sequencing primers and contain regions necessary to bind to the Illumina flow cell).  Following this PCR products of the correct size were recovered using the QIAquick gel extraction kit (Qiagen. USA)