Study On Succession Of Microbial Population In Granulation Of Aerobic Chloroanilines-Degrading Sludge

Chloroaniline compounds are the representative persistent pollutants in the world and attract great environmental concerns due to their toxic ,mutagenic and carcinogenic effects. Microbial degradation is known as a major and effective process for reducing pollution caused by such compounds. Many researches pointed out that the efficiency and stability of biological treatment system and bioremediation process are most related to community structure, functional property and spatial of microbe. Development and application of advanced molecular microbiological techniques such as Denaturing gradient gel electrophoresis (DGGE), Fluorescent in situ hybridization (FISH) would provide new techniques for molecular ecology of microbial community .To investigate the molecular ecological characteristics of microbial population in aerobic CAs-degrading granules, in current work, we used PCR-DGGE to monitor the genetic diversity and dynamic of microbial population in the granulation of aerobic sludge in SBR and SABR for CAs-containing organic wastewater treating.DGGE analysis indicated that microbial population differed obviously during the aerobic degradation of 4-CA and sludge granulation process: Most bands disappeared in inoculation sludge and specific bands appeared in granules. The result, 4-CA degradation process changed the diversity of microbial population, was most probably related to the development of 4-CA-degrading consortium by species' adaptation to the presence of 4-CA. The abundance of microbe in granules from R2 was the highest, followed by R3 and R1.R1 reactor had highly similar population fingerprints between day 10 and day 25 as the C_s was 0.45 because the process of sludge granulation in initial operation progressed slowly, whereas R2 and R3 reactors had a higher granulation velocity but weaker relativity. The microbial population was unstable and changed immediately under the high 4-CA loadings during the aerobic granules growing period. It changed in the response to the decline in 4-CA removal performance of threereactors (R1-R3) during a long-term operation under high 4-CA loading, with the values of Cs ranged from 59.1 to 64.6, from which the community structure of granule from R3 reactor was comparatively stable in the case of 4-CA shock loading.Microbial population diversity of granules from R3-R5 reactors treating different chloroanilines-containing organic wastewater were obviously different. DGGE assay and Phylogenetic analysis confirmed the dominance of P ->* y -Pro-teobacteria^ Planctomycetales^ Flavobacteriales> Clostridiales and Acidobacteria in the 4-CA-degrading aerobic granules, and most of the predominance of bacteria closely related to Thauera sp.Phylogenetic analysis of CAs and aniline-degrading aerobic granules indicated that P -^ Y -Proteobacteria and Flavobacteria were dominant classes and the leading predominance of bacteria were closely related to Pseudomonas sp. and Flavo-bacterium sp.. The diversity of community was higher in granules for treatment of CAs and aniline.