• 한국해양학회지:바다
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• 제8권2호
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• pp.210-224
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• 2003

황산염 환원은 혐기성 해양환경에서 황산염 환원 박테리아가 진행시키는 미생물 반응이다. 황산염 환원 반응은 저층으로 공급되는 유기물 분해의 상당 부분을 담당하며, 이때 발생되는 황화가스의 독성 및 주변 금속과의 높은 반응성, 그리고 유기물 분해시 유리되는 무기 영양염들의 수층 용출 등으로 인해 연안생태계 내의 생물 다양성 및 생지화학적 물질의 순환경로에서 중요한 역할을 한다 여러 해양환경의 퇴적토에서 보고 된 황산염 환원율과 이에 영향을 미치는 주요한 환경요인들에 대해 정리한 결과, 공급되는 유기물과 여러 전자수용체들(산소, 질산염, 산화 철, 망간 등)의 분포가 황산염 환원율 및 유기물 분해시 황산염 환원의 상대적 중요성에 직접 영향을 미치는 것으로 나타났다 아울러 전자수용체의 분포와 유기물의 양과 질을 조절하는 요인으로서 온도, 식생의 유무, 생물교란의 영향에 대해 토의하였다. 끝으로, 우리나라와 같이 갯벌이 발달되고, 유기물 부하가 높은 인공양식장의 가동, 부영양화 등으로 인해 혐기성 환경과 적조의 발생빈도가 점증하는 상황에서 유기(오염)물 분해과정과 영양염 순환 경로를 보다 잘 이해하기 위해서 황산염 환원을 중심으로 한 다양한 혐기성 미생물 생태연구가 중요함을 제안한다.

• Journal of Microbiology and Biotechnology
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• 제22권3호
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• pp.283-291
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• 2012

Bioremediation efforts often rely on the application of surfactants to enhance hydrocarbon bioavailability. However, synthetic surfactants can sometimes be toxic to degrading microorganisms, thus reducing the clearance rate of the pollutant. Therefore, surfactant-resistant bacteria can be an important tool for bioremediation efforts of hydrophobic pollutants, circumventing the toxicity of synthetic surfactants that often delay microbial bioremediation of these contaminants. In this study, we screened a natural surfactant-rich compartment, the estuarine surface microlayer (SML), for cultivable surfactant-resistant bacteria using selective cultures of sodium dodecyl sulfate (SDS) and cetyl trimethylammonium bromide (CTAB). Resistance to surfactants was evaluated by colony counts in solid media amended with critical micelle concentrations (CMC) of either surfactants, in comparison with non-amended controls. Selective cultures for surfactant-resistant bacteria were prepared in mineral medium also containing CMC concentrations of either CTAB or SDS. The surfactantresistant isolates obtained were tested by PCR for the Pseudomonas genus marker gacA gene and for the naphthalene-dioxygenase-encoding gene ndo. Isolates were also screened for biosurfactant production by the atomized oil assay. A high proportion of culturable bacterioneuston was tolerant to CMC concentrations of SDS or CTAB. The gacA-targeted PCR revealed that 64% of the isolates were Pseudomonads. Biosurfactant production in solid medium was detected in 9.4% of tested isolates, all affiliated with genus Pseudomonas. This study shows that the SML is a potential source of surfactant-resistant and biosurfactant-producing bacteria in which Pseudomonads emerge as a relevant group.

• 한국물환경학회지
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• 제18권4호
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• pp.379-386
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• 2002

In this study, estimation model for iron compound originated from upflow, anaerobic fixed bed reactor, which treats sewage domestic wastewater, was developed. The estimation model was formulated by a mathematical expression which was based on the mass balance. Below the HRT of 60 minute, sulfide concentration combining with iron $FeS_2$ is the highest because the maximum sulfate consumption rate $V_{maxS}$ and half-saturation constant of sulfate $K_{mS}$ exert an important effect on the estimation model as temperature was increased. But increment of $FeS_2$ concentration is weakened above the HRT of 60 minutes and represent the lowest value at the HRT of 108 minutes. It implies that liquid phase distribution ratio of sulfide ${\alpha}r$ becomes lower as temperature was increased. While phosphorus concentration combining with iron $Fe_3(PO_4)_3$ is increased as HRT and temperature are increased, which is affected by phosphorus removal rate constant $k_p$. As the result of estimating the iron concentrations of corrosion by the model, the concentration of iron corrosion is higher than any other at the HRT of 108 minute and $20^{\circ}C$. The predicted values were compared with measured ones at different HRT(13.5, 27, 54, 108 min) and temperature(20, 25, $30^{\circ}C$). The experimental data could be fitted with the simulated curves. Therefore, the mathematical expression could be applicable to design full-scale wastewater treatment plants.

• 한국환경보건학회지
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• 제23권3호
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• pp.27-39
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• 1997

This study, collaborated Gifu University, Japan, was performed to analyze chemical pollutants and microorganism and to clarify the distribution of sulfate-reducing bacteria and their insolubilization of heavy metal ions in leachates sampled seasonally between 1994 and 1996 from Nanjido waste landfill site, sampled 4 times between 1995 and 1996 from Pusan and Daejeon waste landfill site, and sampled 1 time between 1992 and 1994 from Hokkaido, Nagoya, Osaka and Hukuoka waste landfill site in Japan. The results were as follows: 1. The temperatures of internal leachate and leachate effluent were 40$\circ$C and 30$\circ$C, respectively, and the pH values of both leachates were about 8.0 at Nanjido waste landfill site. The concentration of SO$_4^{-2}$ gradually increased with the degree of stabilization and that of NO$_3$-N was detected in a part of sampling sites at one and half years, and in all sampling sites at 3 years after completion of landfill. 2. The organic substances in leachate of Nanjido waste landfill site decreased with the degree of stabilization and they were very fluctuated with measuring point and time. The concentration of organic substance and heavy metals in internal leachate were higher than in leachate effluent and those of Cd, Hg, and Pb were lower than detection limit except a part of samples in 1996. 3. APCs in internal leachate and leachate effluent were not much different and the minimum of APCs in internal leachate and leachate effluent were $1.0\times 10^4$/ml and $4.0\times 10^1$/ml, respectively. 4. The maximums of SRBs in Nanjido, Pusan, and Daejeon waste landfill site were 9180 MPN/ml, 24000 MPN/ml, and 348 MPN/ml, respectively and the maximum of SRBs in Japan waste landfill site was 9300 MPN/ml. 5. During 2-week-SRB culture, the values of MPN were high at 50$\circ$C for initial culture period and at 30$\circ$C for last culture period. MPN started to appear at first day and rapidly increased between 7th day and 9th day. 6. Cadmium and copper were insolubilized by SRB within 6 hr and iron and zinc were done within 48 hr. The rates of insolubilization of Cd, Cu, Fe, Zn, T-Cr were 100%, 99.5%, 95.0%, 99.8%, 16.1% after 48 hr treatment with SRB, respectively.

• 디지털융복합연구
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• 제12권8호
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• pp.283-288
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• 2014

석유 제품 지하 저장 공동의 지하수 수질은 공동 인근 매립지 수질의 영향을 받는다. 매립지 주변의 지하수 수질 분석 결과, 시료의 반 정도에서 지하공동 수질에 영향이 미미한 농도의 As, Cu 및 Pb가 검출되었으며, Cd, Hg, $Cr^{6+}$, $CN^-$, TCE, PCE 및 Pheno은 검출되지 않았다. $COD^{Mn}$의 농도는 모든 시료에서 $8.0mg/{\ell}$이하로 유기물질에 의한 지하수 오염은 거의 없는 것으로 분석되었다. 1차, 2차 미생물 분석결과 총박테리아는 각각 $94.84{\times}10^4cells/{\mu}g/m{\ell}$과 $146.26{\times}10^{-4}cells/{\mu}g/m{\ell}$이고 황산환원 박테리아는 $2cells/m{\ell}$이하로 분석되어 지하공동의 수질에 영향이 미미할 것으로 분석되었다. 저장 공동 인근 지역의 지하수 수질 분석은 공동의 수리 지질의 안정성을 향상시키기 위하여 지속적인 조사와 관리가 필요할 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.906-913
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• 2004

A culture-independent molecular phylogenetic survey was carried out on the bacterial community in cold-seep sediment at Edison Seamount, south of Lihir Island, Papua New Guinea. Small-subunit rRNA genes were amplified directly from the sediment DNA by PCR and cloned. The majority of the cloned 16S rRNA gene sequences were most closely related to as-yet-uncultivated microorganisms found in deep-sea sediments, and were primarily affiliated with one of four groups: the $\gamma$-, $\delta$-, and $\epsilon$-subdivisions of Proteobacteria, and Cytophaga-Flavobacterium-Bacteroides. We did not recover any sequences related to cyanobacteria, prochlorophytes, and $\alpha$-Proteobacteria, which are known to occur in great abundance within the surface mixed layer of the Atlantic and Pacific Oceans. The majority of the cloned $\gamma$-and $\epsilon$-Proteobacterial sequences were closely related to chemoautotrophic sulfur-oxidizing symbionts of marine benthic fauna, and the $\delta$-Proteobacterial sequences to sulfate- and sulfur-reducing bacteria, indicating that they might play an important role in chemoautotrophic primary production and the sulfur cycle in the cold-seep area. There results demonstrate the high diversity of the bacterial community in the cold-seep sediment, and substantially expand knowledge of the extent of bacterial diversity in this formidable and unique habitat.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.260-265
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• 2002

Microbiologically influenced Corrosion (MIC) is one of the most deleterious effects of metal microbe interactions. When a fresh metal surface comes in contact with a non-sterile fluid, biofilm formation is ensued. This might result in the initiation of corrosion. The sites and materials where MIC is implicated are versatile. Industries such as shipping, power generation, chemical etc are reported to be affected. The rapid and unexpected failure of AISI type 304 stainless steel was investigated in the laboratory by simulation studies for a period of 4 months. Slime and water samples from the failure site were screened for corrosion causing bacteria. Both aerobic and anaerobic nora were enumerated and identified using PCR techniques. Pseudomonas sp. and Bacillus sp. were the most common aerobic bacteria isolated from the water and slime samples, whilst sulfate reducing bacteria (SRB) were the major anaerobic bacteria. The aerobic bacteria were used for the corrosion experiments in the laboratory. Coupon exposure studies were conducted using a very dilute (0.1%V/V) nutrient broth medium. The coupons after retrieval were observed under a Scanning Electron Microscope (SEM) for the presence of MIC pits. Compared to sterile controls, metal coupons exposed to Pseudomonas sp and Bacillus sp. showed the initiation of severe pitting corrosion. However, amongst these two strains, Psudomonas sp. caused pits in a very short span of 14 days. Towards the end of the experiment, severe pitting was observed in both the cases. The detailed observation of pits showed they vary both in number and shapes. Whilst the coupons exposed to Bacillus sp. showed widely spread scales like pits, those exposed to Pseudomonas sp. showed smaller and circular pits, which had grown in number and size by the end of the experiment. From these results it is inferred that the rapid and unexpected failure of 304 SS might be due to MIC. Pseudonwnas sp. could be considered as the major responsible bacteria that could initiate pits in the metallic structures. As the appearance of pits was different in both the tested strains, it was thought that the mechanisms of pit formation are different. Experiments on these lines are being continued.

• 인간식물환경학회지
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• 제23권4호
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• pp.455-464
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• 2020

Background and objective: This study was conducted to examine changes in the composition and physiological activity of Gardenia Fructus after being roasted. Methods: The antioxidant, anti-inflammatory and antibacterial activity of Gardenia Fructus was evaluated using the Gardenia Fructus (GF) and roasted Gardenia Fructus (RGF) ethanol extracts, and their components were analyzed through HPLC. Results: As a result, it was confirmed that the content of gardenoside and geniposide decreased and the content of genipin increased when GF was roasted. The total content of polyphenols was 54.5 ± 2.18 mg gallic acid equivalents (GAE) per gram of the GF extract and 69.6 ± 0.36 mg GAE per gram of the RGF extract. As a result of evaluating 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, both the GF and RGF extracts showed the similar activity to ascorbic acid at the concentrations of 1 mg/mL or higher. In RAW 264.7 macrophages stimulated by lipopolysaccharides (LPS), the RGF extract showed a higher effect of reducing NO production, and significantly reduced the expression of an inflammatory cytokine, IL-6. As a result of evaluating the antimicrobial activity, the RGF extract showed higher antimicrobial activity against Escherichia coli and Bacillus subtilis. In the dextran sulfate sodium salt (DSS) induced inflammatory bowel disease mouse model, the RGF extract reduced the weight of the spleen, and both the GF and RGF extracts reduced the number of bacteria in the colon. Conclusion: Therefore, it has been confirmed through this study that roasting at a high temperature changes the main components of the GF extract and increases its biological activity. The RGF extract is expected to be used as a natural material with antioxidant, anti-inflammatory and antibacterial effects.

• 미생물학회지
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• 제53권2호
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• pp.83-96
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• 2017

부산시 영도구의 혁신지구의 인공해수천은 높아진 하상과 조류의 특성으로 인해 물이 순환되지 않고 더구나 주위의 오수가 유입되고 있어서 수질이 나빠지고 악취를 발생하고 있다. 이 문제를 해결하기 위한 방안으로 가장 오염되고 조류이동을 감안한 하천의 지점에 생물증강법을 적용하여 친환경적, 효율적으로 하천을 정화하고자 하였다. 현장에서 활성화된 복합미생물을 가장 오염된 지점(Site 2)에 7~10일 간격으로 투입하여, 수질의 pH, 온도, DO, ORP, SS, COD, T-N, 및 T-P를 측정하였고 또한 하상퇴적토의 COD 및 미생물군집을 분석하였다. 13개월 후 Site 2의 수질 SS, COD, T-N 및 COD (퇴적토)의 처리효율은 각각 51%, 58%, 27% 및 35%으로 나타났으나 T-P는 오히려 47% 증가를 보였다. 대부분의 측정지점에서 황산염환원세균(sulfate reducing bacteria)그룹 (Desulfobacteraceae_uc_s, Desulfobacterales_uc_s, Desulfuromonadaceae_uc_s, Desulfuromonas_g1_uc and Desulfobacter postgatei)과 Anaerolinaeles의 밀도는 대체적으로 생물증강에 의한 정화가 진행될수록 감소하였으며, 반면에 Gamma-proteobacteria (NOR5-6B_s and NOR5-6A_s), Bacteroidales_uc_s, 및 Flavobacteriales_uc_s의 밀도는 증가하는 경향이었다. 상대적으로 COD가 낮고 DO가 높은 청정지점인 St. 4에서는 호기성미생물인 Flavobacteriaceae_uc_s가 우점하였다. 이러한 미생물군은 하천의 정화과정을 추적할 수 있는 지표미생물로 활용될 수 있을 것으로 판단되었다. 생물증강 시행 후의 대표적 시점 퇴적토시료의 미생물군집 alpha diversity 지수(OTUs, Chao1 및 Shannon 지수)는 시행 전에 비해 감소하는 경향을 보였으며, 또한 beta diversity 분석기법(fast unifrac 분석)으로 분석한 결과 정화 전이나 초기에 비해서 정화가 진행될수록 전반적으로 시료에 무관하게 미생물군집의 유사성을 보여 생물증강이 현장 토착 미생물의 군집구조를 변화시키고 있음을 확인하였다. 이러한 사실로 보아 본 복합미생물에 의한 현장 생물증강법은 brine water 및 담수로 이루어진 오염된 하천을 환경친화적, 경제적으로 정화할 수 있는 대안으로 판단이 되었다.

• Journal of Microbiology
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• 제39권3호
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• pp.195-201
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• 2001

The effect of moisture content an the reductive dechlorination of polychlorinated biphenyls and population dynamics of dechlorinating microorganisms was investigated in sediments spiked with Aroclor 1248. In sediment slurry with an overlying water layer, dechlorination ensued after a 4-week lag period and reduced the average number of chlorines per biphenyl from 3.91 to 3.15 after 48 weeks. In the sediments of reduced moisture content, however, dechlorination occurred after a lag period of 12 weeks and decreased the average number of chlorines per biphenyl to only 3.62, and the dechlorination rate was also slower. When the population size of dechlorinators, methanogens, and sulfate-reducing bacteria was determined by the most probable number techniques, however, no difference was found between the slurry and the low-moisture sediments, except for methanogens. The growth of dechlorinating populations coincided with the end of the lag period and they then increased by 3 orders of magnitude in two conditions. Specific growth rate of dechlorinators showed little difference between the slurry and the low-moisture sediments; however, growth yield was high in the sediments of reduced moisture content. The reduction of sediment moisture decreased the dechlorination rate and extent of PCBs but did not inhibit the growth of PCB dechlorinators.