"DNA was extracted using Genelute DNA extraction kit (Sigma).16S rRNA genes were amplified by PCR with primers 27FYM and 519R, incorporating a unique barcode and sequencing adapters. Amplicons were purified, quantified and pooled in equimolar proportions. Emulsion PCR and unidirectional sequencing of the library was performed using the Lib-L kit and Roche 454 GS-FLX Titanium sequencer."