• Korean Journal of Microbiology
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• v.46 no.2
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• pp.169-176
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• 2010

A pilot-scale wastewater treatment plant combined with rotating biological contactor and tapered aeration reactors was operated with the wastewater discharged from a food factory for 5 months. The bacterial communities of this plant were investigated by terminal restriction fragment length polymorphism (T-RFLP) and phylogenetic analysis of 16S rRNA genes. In spite of high concentration of nitrogen and phosphorus as well as organic carbon, removal efficiency of chemical oxygen demand, total nitrogen, and total phosphorus was 98%, 93%, and 95%, respectively. Bacterial community at the initial operation stage was clearly distinguished from that of the stable operation stage. The most predominant phylum in the sample of stable stage was Bacteroidetes. Major population of operation period was Haliscomenobacter, Sphaerotilus, and candidate division TM7, which were classified as filamentous bacteria. However, sludge bulking caused by these bacteria was not observed. The population that has a close relationship with Haliscomenobacter increased during the stable operation stage, emerging as the most predominant group. These results suggest that the filamentous bacteria participated in nutrient removal when using rotating biological contactor and tapered aeration reactor.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.444-449
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• 1992

A total of 858 heterotrohic bacteria were isolated and analyzed hy numerical method to investigate the heterotrophic hacterial community structure in Naktong Estuary. Although the values of H' (Shannon's diversity index). ranged between 1.54 and 3.49. were similar with those of the data hefore the construction of Naktong River barrage, however J' (evenness index. 0.31-0.80) was reduced. Physiological tolerance index for water temperature ($P_{s}$) was high at St.l and 2 whose depthes arc shallower than the other stations. and indices for pH ($P_{h}$) and salinity ($P_{s}$) were high at St. 2. 3. 4 where freshwater and seawater arc mixed. The predominant clusters were identified as Aeromonas. Vihrio. Pseudomonas. Acinelobacter-Morexella. Alcaligenes. Flavobacterium. Micrococcaccae. and Enterohacteriaceae. The kinds nf the isolates were similar with the previous result. hut the dominant genus was changed. These results suggest that the environmental changes in Naktong Estuary affect the hacterial physiological adaptation rather than the composition of heterotrophic hactcrial community.

• 한국생태학회:학술대회논문집
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• 1998.05a
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• pp.60.2-60.2
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• 1998

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.141.2-141
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• 2000

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.219-225
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• 2006

Bacterial community structure in the Juam Reservoir was analysed using fluorescent in situ hybridization (FISH) technique from April 2005 to January 2006. Total bacterial numbers varied in the range of 1.58 ${\sim}\;2.73{\times}\;10^6\;cells\;mL^{-1}$ proportional to the concentration of chi-a and had the minimal value in January. The ratios of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclass proteobacteria and Cytophaga-Flavobacterium (CF) group to total bacteria ranged from 45.1% to 77.5%, and the ratios of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclasses to total bacteria in June and September with the concentration of chi-a measured were lower than those ratios in April and January. It suggests that enriched growth of Microcystis aeruginosa may inhibit the metabolic activlty of ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}$-subclass proteobacteria. However, the ratio of CF group bacteria represented no large change depending on algal bloom. In terms of nitrifying bacteria, the numbers of ammonia-oxidizing bacteria ranged from 9.9 ${\times}\;10^4\;to\;25.5\;{\times}10^4\;cells\;mL^{-1}$ with sharp fluctuation whereas those of nitrite-oxidizing bacteria varied in 8.7${\sim}9.8{\times}10^4\;cells\;mL^{-1}$ without noticeable change except the maximal value of $20.3{\times}10^4\;cells\;mL^{-1}$ in January maybe due to the high DO.

• Microbiology and Biotechnology Letters
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• v.42 no.1
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• pp.41-50
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• 2014

In this study, the performances of PVA-encapsulation and non-encapsulation in a fed-batch bioreactor system were compared for biohydrogen production. Hydrogen production in the PVA-encapsulation bioreactor was not significantly different in comparison to the non-encapsulation bioreactor. However, the hydrogen gas in the encapsulation bioreactor could be stably produced when it was exposed to environmental difficulties such as pH impact by the accumulation of organic acids as fermentative metabolic products. Bacterial communities by DGGE analysis were differently shifted between the PVA-encapsulation and non-encapsulation bioreactors from the initial sludge. The community of hydrogen producing bacteria was stable during the experimental period in the PVA-encapsulation bioreactor compared to the non-encapsulation method. The absolute quantitation of the DNA copy number by a high-throughput droplet digital PCR system for six genera contributed to hydrogen production showing that the numbers of dominant bacteria existed at similar levels in the two bioreactors regardless of encapsulation. In both of two bioreactors, not only Clostridium and Enterobacter, which are known as anaerobic hydrogen producing bacteria, but also Firmicutes, Ruminococcus and Escherichia existed with $1{\times}10^5-1{\times}10^6$ copy numbers of ml-samples exhibiting rapid growth during the initial operation period.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.3
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• pp.227-233
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• 2010

This study examined microbial community structures (MCSs) according to environmental factors through DGGE analysis and comparison in various soils collected from near army bases and gas stations. As a result, the similarities based on DGGE band profiles showed the closer relationship in regional properties than in pollution characteristics, probably due to the degree of weak contamination. The highly contaminated samples with oil revealed low MCS similarities with others in the same region and very low with all the other samples in the other regions. Thus the microbial community structure would more be affected by region-based natural factors than by contamination factors in case of minor pollution. All the dominant culturable bacterial species were involved in firmicutes or high GC Gram+ in a major portion of soil samples and the highly oil-contaminated samples contained Arthrobacter, Bacillus, Methylobacterium, Clavibacter, Streptomyces and Nocardia as reported genera, and Leifsonia as a unreported genus.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.148-154
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• 2009

Composting is a biological process converting solid organic waste into valuable materials such as fertilizer. The change of bacterial populations in a composting reactor of food waste was investigated for 2 months. Based on shifts in temperature profile, the composting process could be divided into the first phase ($2^{\circ}C\sim55^{\circ}C$), the second phase ($55^{\circ}C\sim97^{\circ}C$), and the third phase ($50^{\circ}C\sim89^{\circ}C$). The number of total bacteria was $1.66\times10^{11}$ cell/g, $0.29\times10^{11}$ cell/g, and $0.28\times10^{11}$ cell/g in the first, second, and third stages, respectively. The proportions of thermophiles increased from 33% to 89% in the second stage. T-RFLP analysis and nucleotide sequencing of 16S rRNA gene demonstrated that the change of bacterial community structure was coupled with shifts in composting stages. The structure of bacterial community in the ultra-thermophilic second stage reflected that of seeding starter. The major decomposers driving the ultra-thermophilic composting were identified as phylotypes related to Bacillus and Pseudomonas.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.274-274
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• 2008

• Korean Journal of Microbiology
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• v.37 no.4
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• pp.265-272
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• 2001

The diversity of acid-tolerant epiphytic bacterial communities on deciduous oak tree (Quercus dentate Thunb.) leaves was examined both in the natural forest area with a clean air and in the industrial estate to assess effects of acidic depositions to the phyllosphere using 16S rDNA sequence data. A total of 444 acid-tolerant epiphytic bacterial clones were obtained, resulting in 17 phylotypes by performing a analysis of restriction fragment length polymorphism (RFLP) for PCR-amplified 16S rDNA products. A very low diversity of dominating acid tolerant bacterial communities in both areas was found, just 2 subphyla groups, $\gamma$-Proteobacteria and low-G+C gram-positive bacteria. As tree leaves grow older, diversities of acid-tolerant bacteria on them significantly increased. The community structure of acid-tolerant epiphytic bacteria consisted of Pseudomonas and Enterobacteriaceae groups in the $\gamma$-Proteobacteria subphylum, and Streptococcaceae and Staphylococcus groups in the low-G+C gram-positive bacteria subphylum. The direct influence of acidic depositions on bacterial phylogenetic composition could not be detected especially when higher taxonomic levels such as subphylum, but at narrower or finer levels it could be observed by a detection of Xanthomonadales group belonged to the $\gamma$-Proteobacteria only in the industrial area and of Acetobacteraceae group belonged to the $\alpha$-Proteobacteria. There remains that these specific acid-tolerant epiphytic bacterial groups could be used as indicators for assessing effects of acidic depositions on the phyllosphere.