title: 16S rRNA of enriched methanogenic biofilm from top of cathode in reactor 2
design: Sequencing libraries were prepared from the purified amplicon libraries using a second PCR. Each PCR reaction (25 L) contained PCRBIO HiFi buffer (1x), PCRBIO HiFi Polymerase (1 U/reaction) (PCRBiosystems, UK), adaptor mix (400 nM of each forward and reverse) and up to 10 ng of amplicon library template. PCR was conducted with the following program: Initial denaturation at 95 C for 2 min, 8 cycles of amplification (95Cfor20s,55Cfor30s,72Cfor60s)andafinalelongationat72Cfor5min. Theresulting sequencing libraries were purified using the standard protocol for Agencourt Ampure XP Beads (Beckman Coulter, USA) with a bead to sample ratio of 4:5. DNA was eluted in 25 L of nuclease free water (Qiagen, Germany).