Real time PCR quantification of ammonia-oxidizing bacteria in aerobic granular sludge and activated sludge influenced by pentachlorophenol

Abstract:

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 4.28×10⁷±5.44×10⁶cells/g dried sludge and 2.51×10⁹±8.61×10⁸cells/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.