Title Analysis of Microbial Communities Using Culture-dependent and Culture-independent Approaches in an Anaerobic/Aerobic SBR Reactor
Author Shipeng Lu1, Minjeong Park1, Hyeon-Su Ro1,2, Dae Sung Lee3, Woojun Park1,4, and Che Ok Jeon1,*
Address 1Division of Environmental Biotechnology & PMBBRC, Gyeongsang National University, GyeongNam 660-701, Republic of Korea , 2Department of Microbiology & Research Institute of Life Science, Gyeongsang National University, GyeongNam 660-701, Republic of Korea, 3School of Environmental Science & Engineering, POSTECH, Kyoungbuk 790-784, Republic of Korea, 4Division of Environmental Science and Ecological Engineering, Korea University, Seoul 136-701, Republic of Korea
Bibliography Journal of Microbiology, 44(2),155-161, 2006,
DOI
Key Words microbial community, PCR, culturability
Abstract Comparative analysis of microbial communities in a sequencing batch reactor which performed enhanced biological phosphorus removal (EBPR) was carried out using a cultivation-based technique and 16S rRNA gene clone libraries. A standard PCR protocol and a modified PCR protocol with low PCR cycle was applied to the two clone libraries of the 16S rRNA gene sequences obtained from EBPR sludge, respectively, and the resulting 424 clones were analyzed using restriction fragment length polymorphisms (RFLPs) on 16S rRNA gene inserts. Comparison of two clone libraries showed that the modified PCR protocol decreased the incidence of distinct fragment patterns from about 63% (137 of 217) in the standard PCR method to about 34% (70 of 207) under the modified protocol, suggesting that just a low level of PCR cycling (5 cycles after 15 cycles) can significantly reduce the formation of chimeric DNA in the final PCR products. Phylogenetic analysis of 81 groups with distinct RFLP patterns that were obtained using the modified PCR method revealed that the clones were affiliated with at least 11 phyla or classes of the domain Bacteria. However, the analyses of 327 colonies, which were grouped into just 41 distinct types by RFLP analysis, showed that they could be classified into five major bacterial lineages: α, β, γ- Proteobacteria, Actinobacteria, and the phylum Bacteroidetes, which indicated that the microbial community yielded from the cultivationbased method was still much simpler than that yielded from the PCR-based molecular method. In this study, the discrepancy observed between the communities obtained from PCR-based and cultivation-based methods seems to result from low culturabilities of bacteria or PCR bias even though modified culture and PCR methods were used. Therefore, continuous development of PCR protocol and cultivation techniques is needed to reduce this discrepancy.
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