The Analysises Of Microbial Community Dynamics And Functional Groups In Autotrophic Denitrifying Sulfide Removial Reactior

PCR-single-strand conformation polymorphism (SSCP) was adapted to investigate microbial community structure and dynamics in simultaneous desulfurification and denitrification bioreactor of integrative and separated process. At the same time, PCR-DGGE technology was used to analyze and monitor autotrophic denitrification function bacteria. DNA molecules in SSCP profiles were cloned and sequenced.Microbial community was analyzed in simultaneous desulfurification and denitrification bioreactor of integrative process by SSCP. After recovery, amplification, and clone of DNA molecules in SSCP bands, total of 23 clone sequences were obtained. These sequences belong to 5 phyla, i.e. Chloroflexi 13.04%,Bacteroidetes 26.07%,Proteobacteria 52.17% ,Firmicutes 8.70%. On the day 22, Dysgonomonas emerged in the reactor, and it competed for lactate with Sulfate-Reducing Bacteria. So Sulfate-Reducing Bacteria declined in concentration gradually. The sulfate-removal rate dropped from 92% to 76%. On the day 47, Sulfurospirillum emerged in the reactor. The metabolism of Sulfate Reducing Bacteria was suppressed obviously. In simultaneous desulfurification and denitrification bioreactor of integrative process, two kinds of autotrophic simultaneous denitrification and desulfurification bacteria were found, Pseudomonas sp.and Paracoccus sp.. They reduced sulfate and nitrate simultaneously in the bioreactor, which were the most important function bacteria. They were heterotrophic in anaerobic condition, and utilized sulfide as electron donator, and the nitrate was deoxidized to nitrenes and nitrogen. Through the SSCP analysis of the bioreactor of separated process, the structure of microbial community was better than that of integrative process.After recovery, amplification, and clone of DNA molecules in SSCP bands, total of 25 clone sequences were obtained. These sequences belong to 4 phyla, i.e. Proteobacteria 52.0%, Bacteroidetes 24.0%, Firmicutes 12.0%,Chloroflexi 12.0%. From the day 1 to 22, Desulfomicrobium was predominant together with Sulfurovum, and Desulfomicrobium increased in concentration as the operation of the bioreactor. From the day 23 to 32, the populations of Desulfomicrobium, Thauera, Sulfurovum got to rich and stable. The populations of Tannerella, Anaerophaga reduced and died out. During the operation of the reactor, Desulfomicrobium, Thauera, Sulfurovum, Acetivibrio, Anaerolinea existed all the time. Pseudomonas, Azoarcus were denitrification bacterium. Pseudomonas was heterotrophic at anaerobic condition, and utilized nitrate.The nitrate was deoxidized to nitrenes and nitrogen. They were the function bacteria in simultaneous desulfurification and denitrification bioreactor of separated process.The result showed that there were more complex microbe species in the bioreactor of integrative process comparising with that of separated process. In this study, it showed that only an reaction of sulfide oxygenation existed in the bioreactor of separated process. So the community complexity was lower. In the bioreactor of integrative process, Acid-producing Bacteria competed with Sulfate-Reducing Bacteria. The activity and populations of Sulfate-Reducing Bacteria declined gradually, and autotrophic simultaneous denitrification and desulfurification bacterium decreased. So the efficiency of the reactor dropped. In this study, in order to analyze microbial community and monitor function bacterium faster and better, we optimized PCR-SSCP technology. The best condition was as follows: acrylamide to N,N-dimethylacrylamide in 12% PAG gel was 49:1. The rate of Formamide deionized in denaturing loading buffer was 1:3. SSCP gel ran at 300 V for 18 h , at 4℃.