부산대학교 도서관

In enhanced biological phosphorus removal (EBPR) plants, the presence of glycogen-accumulating organisms (GAO) has been hypothesized to be one of causes of the deterioration in P removal process by out-competing with polyphosphate-accumulating organisms (PAO). Putative GAO, belonging to the Gammaproteobacteria (GB group) was studied in lab-scale reactors to determine their diversity, physiological, and metabolic properties. Community analysis using 16S rRNA gene clone libraries revealed that the predominant clones (GB_G8) formed a clear distinctive lineage from the reported seven GAO GB subgroups within the Gammaproteobacteria and they were not targeted by the known GB and GB_1 (GAOQ989) fluorescence in situ hybridization (FISH) probes. FISH/Microautoradiography (MAR) approaches showed that the GB_G8 subgroup bacteria were coccus (4-5μm in size) and they took up acetate under the anaerobic condition while did not accumulate polyphosphate under the following aerobic condition, suggesting that the novel GB_G8 subgroup had typical GAO property. Polyhydroxyalkanoate (PHA), but not polyphosphate (polyP) granules were detected from the cells by chemical staining methods. GB_G8 subgroup microorganisms were selectively sorted using fluorescence-activated cell-sorting (FACS) and PHA synthase (phaC) and polyphosphate kinase (ppk) genes were analyzed using degenerate PCR primer sets. As the results, only primer sets targeting phaC genes produced PCR amplicons which shared a high degree of similarities with those of proteobacteria, and these results might give a clue to explain GAO physiological properties.
생물학적 인 제거(EBPR, enhanced biological phosphorus removal) 공정에서 글리코겐 축적 미생물(GAOs, glycogen-accumulating organisms)은 인 축적 미생물 (PAOs, polyphosphate-accumulating organisms)과의 종간 경쟁에 의해 이들의 인 제거 과정을 저하시기는 요인 중 하나로 작용한다고 여겨져 왔다. 본 연구에서는 GAO로 추정되는 미생물(Gammaproteobacteria에 속하는 GB group)의 생물다양성, 생태생리학적 특성과 물질대사적 속성을 결정하기 위하여 실험실 조건 내 반응기에서 실험을 진행하였다. 16S rRNA gene clone libraries를 사용한 군집 분석에서, 우점하는 clone (GB_G8)은 보고된 GB group 내의 7개의 GAO subgroup과는 서로 다른 계통학적 특성을 보였고, 알려진 GB, GB_1 (GAOQ989) FISH (fluorescence in situ hybridization) probe에 의해 검출되지 않았다. FISH/ Microautoradiography (MAR) approach는 GB_G8이 4-5um의 구균이며, 이들은 혐기성 조건에서 acetate를 흡수하지만 호기성 조건에서 인을 축적하지 못하는 전형적인 GAO의 특징을 나타내었다. 또한, 화학적 염색 방법에 의해 polyphydroxyalkanoate (PHA)는 검출되었으나 polyphosphate (polyP)는 검출되지 않았다. 물질대사에 대한 특성을 살펴보기 위해 GB_G8 subgroup에 속하는 미생물을 fluorescence-activated cell-sorting (FACS)를 사용하여 분획하였고, PHA synthase (phaC)와 polyphosphate kinase (ppk) 유전자를 확인하기 위하여 degenerate PCR primer sets를 사용한 PCR분석을 실시하였다. 그 결과, phaC를 나타내는 PCR amplicon이 확인되었고, 이것은 proteobacteria의 phaC와 높은 유사도를 보여 분리된 세포가 GAO 의 생리적인 특성을 지니고 있음을 설명하는 근거를 제시하였다.