The Microbial Community Structure In Anaerobic Systems For Chlorophenols And Nitrobenzene Degradation

Anaerobic biodegradation could degrade poisonous organic substance with lowerenergy-consuming,higher efficiency without secondary pollution than aerobicbiodegradation．As two kinds of representative priority pollutants in environments,chlorophenol compounds (2-monochlorophenol,4-monochlorophenol,2,4-dichlorophenol) and nitrobenzene were studied in order to analyze the microbialcommunity structure in these anaerobic bioreactors．The experiments were carried outon continuously upflow anaerobic sludge bed (UASB) and in batch serum bottles．The sludge samples were treated with molecular biological techniques,including theextraction of total DNA,PCR amplification,DGGE profiles analysis,cloning,sequencing,flow cytometry with FITC-labeled probes,targeted for Archaea,Bacteria,sulfate reducing bacteria(SRB) and methanogens in these anaerobic systemdegradation for chlorophenols and nitrobenzene．Results confirmed that thesemolecular biological techniques were effective on anaerobes community analysis．17 kinds of archaeal species were found in inoculum granular sludge．Afteracclimation with 2-CP and 4-CP respectively,the archaeal species number increasedto 23 and 19 correspondingly．7 kinds of archaeal species were found among theinoculum sludge,2-CP-acclimated sludge and 4-CP-acclimated sludge,which maybedominant Archaea in anaerobic systems degradation for chlorophenols．4 kinds ofAcidobacteria were found both in the inoculum sludge and in the 2-CP-acclimatedsludge．8 kinds of Acidobacteria disappeared after acclimate by 2-CP,andsimultaneously 7 kind of Acidobacteria were found in the 2-CP-acclimated sludge．The Archaea community structure in anaerobic granular sludge-suspendedcarrier biofilm bioreactor (ASBR) for 2,4-dichlorophenol-degrading was analyzed．15,10 and 14 kinds of archaeal species were found in the bottom,the medium and theupper latitude of ASBR respectively．10 kinds of archaeal species were found indifferent latitude of ASBR．After the inoculum sludge was acclimated with 2,4-DCP,archaeal diversity decreased dramatically,especially in the bottom sludge of ASBR．In inoculum sludge and anaerobic bioreactors degradation for chlorophenols,the content of Methanobacterium was higher than Methanosaeta and Methanogenium,which indicated that Methanobacterium were the dominant methanogens in anaerobicbioreactors degradation for chlorophenols．The effects of Cd²⁺,Cu²⁺ and Ni²⁺ at 300 mg／L on anaerobic microbialcommunities in 2-CP-degradation system were examined．The metal injection withhigh concentration changed both the bacterial and the archaeal community structure．In the control sludge acclimated with 2-CP,23 kinds of arachaeal species were found．After injection with Cu²⁺ for 3 d,18 kinds of arachaeal species were found and only 9kinds of archaeal species were found after 10 d recovery without Cu²⁺．The reductionof archaeal diversity resulted in the intensively inhibition and the longest time forrecovery．After injection with Cd²⁺ for 3 d．30 kinds of arachaeal species were foundand only 14 kinds of archaeal species were found after 10 d recovery without Cd²⁺．The reduction of archaeal diversity resulted in the slow recovery．After injection withNi²⁺ for 3 d．30 kinds of arachaeal species were found and then 39 kinds of archaealspecies were found after 10 d recovery without Ni²⁺．The increase of archaealdiversity resulted in fast recovery even if the intensively inhibition．Archaea in anaerobic bioreactors degradation for nitrobenzene at differentconditions were analyzed．In the control sludge treated nitrobenzene at 25mg／L,93kinds of archaeal species were found．89 kinds of archaeal species were found both innitrobenzene-degradation system at neutral and alkaline condition respectively．Withthe addition of FeCl₂(100mg／L,neutral condition),87 kinds of archaeal species werefound in nitrobenzene-degradation system．74 kinds of common archaeal specieswere found in all nitrobenzene-degradation system．The archaeal diversity innitrobenzene-degradation systems exceeded that of chlorophenols-degradationsystems．Except the dominant archaeal species which were found inchlorophenols-degradation systems,such as Uncultured archaeon(TA05／TA04／TA01),Methanothrix soehngenii,Methanosaeta concilii etc．,archaealspecies in nitrobenzene-degradation systems were varied and distributed abordly．Thearchaeal species in nitrobenzene-degradation systems focused on Methanobacterium,Methanococcus,Methanospirillum and Methanoculleus．In the outside cycling anaerobic reactor (OCAR) treated with municipal wastewater at normal temperature,18,45 and 21 kinds of archaeal species werefound in the bottom,the medium and the upper latitude of OCAR respectively．14kinds of common archaeal species were found in different latitude of OCAR．In each latitude of OCAR,the content of Methanobacterium were less thanMethanosaeta and Methanogenium．In the bottom and the upper of OCAR,Methanosaeta was the dominant methanogens with the highest content．While in themedium of OCAR,Methanogenium was the dominant methanogens with the highestcontent．In different latitude of OCAR,the content of SRB was less than that ofMethanosaeta but more than that of Methanobacterium．...