ABSTRACT
Effect of p-nitrophenol shock on microbial populations and sludge activity in UASB reactor was studied by DGGE-PCR of 16S rDNA fragments and detection of COD removing and biogas yield.The results showed that p-nitrophenol seriously inhibited the sludge activity,resulting in the drop of biogas and COD removing rate.The 40mg/L p-nitrophenol had more inhibition than 20mg/L p-nitrophenol.It would take 27 and 16 days respectively for reactor to recover after 40mg/L and 20mg/L p-nitrophenol shock.The diversity of eubacteria and methanogens were also effected by the p-nitrophenol shock.The variation of eubacteria was more than that of methanogens after p-nitrophenol shock.The drop of biogas was mainly related to the variation of Methanosaeta sp.and Methanomicrobia sp.after p-nitrophenol shock.Among the eubacteria the population of Chloroflexi sp.、Bacteroide sp.and Anaerovibrio sp.decreased greatly after p-nitrophenol shock.And more,the Rheinheimera sp disappeared after 40mg/L p-NP treatment.But the Flavobacteria sp.appeared after p-nitrophenol shock,which was probably related to the degradation of p-NP.