Molecular and ecological analyses of microbial community structures in biofilms of a full-scale Aerated Up-Flow Biobead process.
Molecular and cultivation techniques were used to characterize the bacterial communities of biobead reactor biofilms in a sewage treatment plant to which an Aerated Up-Flow Biobead process was applied. With this biobead process, the monthly average values of various chemical parameters in the effluent were generally kept under the regulation limits of the effluent quality of the sewage treatment plant during the operation period. Most probable number (MPN) analysis revealed that the population of denitrifying bacteria was abundant in the biobead #1 reactor, denitrifying and nitrifying bacteria coexisted in the biobead #2 reactor, and nitrifying bacteria prevailed over denitrifying bacteria in the biobead #3 reactor. The results of the MPN test suggested that the biobead #2 reactor was a transition zone leading to acclimated nitrifying biofilms in the biobead #3 reactor. Phylogenetic analysis of 16S rDNA sequences cloned from biofilms showed that the biobead #1 reactor, which received a high organic loading rate, had much diverse microorganisms, whereas the biobead #2 and #3 reactors were dominated by the members of Proteobacteria. DGGE analysis with the ammonia monooxygenase (amoA) gene supported the observation from the MPN test that the biofilms of September were fully developed and specialized for nitrification in the biobead reactor #3. All of the DNA sequences of the amoA DGGE bands were very similar to the sequence of the amoA gene of Nitrosomonas species, the presence of which is typical in the biological aerated filters. The results of this study showed that organic and inorganic nutrients were efficiently removed by both denitrifying microbial populations in the anaerobic tank and heterotrophic and nitrifying bacterial biofilms well-formed in the three functional biobead reactors in the Aerated Up-Flow Biobead process.
Ju
Dong-Hun
DH
Department of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Korea.
Choi
Min-Kyung
MK
Ahn
Jae-Hyung
JH
Kim
Mi-Hwa
MH
Cho
Jae-Chang
JC
Kim
Taesung
T
Kim
Taesan
T
Seong
Chi Nam
CN
Ka
Jong-Ok
JO
D001419:Bacteria / Q000145:classification*; D018441:Biofilms; D019149:Bioreactors; D004269:DNA, Bacterial / Q000032:analysis; D004463:Ecology; D004586:Electrophoresis; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics
D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S