RNA-Seq of microorganism
Before DNA extraction, sludge samples were centrifuged at 8000 g to remove the supernatant. DNA was extracted from sludge sediments of three replicate reactors using an EZNA Soil DNA kit (Omega Bio-Tek, Inc., Norcross, GA, USA) and then pooled. Amplicon libraries were constructed for pyrosequencing using the bacterial fused primers 341 F and 805 R for the V3-V4 region of the 16S rRNA gene.