aerobic granules
The matured aerobic granules were collected from the reactor. Approximately 0.2 g of wet sludge sample was collected. To effectively extract DNA, the aerobic granules were crushed and then washed with PBS (Phosphate-buffered saline) buffer for three times. After centrifugation, the pellet was used for DNA extraction with PowerSoil DNA isolation kit (MO BIO Laboratories Inc., USA). The DNA samples were then amplified, targeting V3-V4 hypervariable region of 16S rRNA. The primer used were CACGATCCTACGGG (forward) and GGACTAC (reverse). Amplicons were sequenced by MiSeq platform (Illumina, USA).