[Real time PCR quantification of ammonia-oxidizing bacteria in aerobic granular sludge and activated sludge...

The V2 region of the 16S ribosomal DNA of the ammonia-oxidizing bacteria (AOB) was amplified directly from the environmental sample by using the specific PCR primers. The purified PCR product was cloned into T-vector and was identified as 16S rDNA fragment of AOB by sequencing and Real-time PCR method. Then, the recombined plasmid was used as standard molecule sample in Real-time PCR for AOB quantification. The numbers of the AOB were monitored in samples of both aerobic granular sludge and activated sludge influenced by PCP by using Real-time PCR. The results showed that the numbers of AOB in aerobic granular sludge and activated sludge were 4.28 x 10(7) 5.44 x 10(6) cells/g dried sludge and 2.51 x 10(9) +/- 8.61 x 10(8) cells/g dried sludge without PCP in the reactors, respectively. With the increase of PCP concentration (from 0mg/L to 50mg/L), the numbers of AOB in both types of sludge had no obvious change( P > 0.05) . The numbers of AOB had no obvious correlation with ammonia removal ( P > 0.05) . The main effect of PCP on AOB in both types of sludge was to inhibit their metabolic activity.