• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.477-482
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• 1992

A bacterial strain Acinetobacter calcoaceticus was examined for its ability to degrade fats, oils and hydrocarbons, and tested for the possibility of application in wastewater treatment. All fats and oils tested were degraded by the strain. About 60% of hexadecane, 26% of fish oiL and 40-54% of vegetable oils were consumed respectively in shaking-flask culture. Saturated fatty acid compositions were about 55% in fish oil and 6-12% in vegetable oils. Increases in cell mass were accompanied with decreases in the concentrations of carbon sources. When jar fermentor in place of shaking-flask was used as a culturing vessel. above 80% of all carbon sources was consumed and yield of cell mass was improved to nearly 1.00. Synthetic wastewaters containing 3% of fat, oil, or hydrocarbon as a sale ca,bon source were treated sequentially with A. calcoaceticus first and then exposed to activated sludge. The concentrations of carbon sources were decreased below 0.06% through the process, and the concentrations of suspended solids were lower than 53 mglml. The data imply the potential use of A. calcoaceticus in wastewater treatment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.220-223
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• 2001

본 연구에서는 endosulfan으로 오염된 토양을 in-situ flushing으로 정화시 발생되는 세척 유출수의 고정화 미생물에 의한 처리 효율 및 적용성을 검토하였다. 초기 endosulfan 농도 및 pH가 각각 5mg/L, 5.6인 세척유출수의 체류시간을 1, 3, 5시간으로 하여 고정화미생 물 충진 컬럼에 적용한 결과, 제거효율은 각각 62, 82, 89%로 체류시간이 증가될수록 향상되었으며 3가지 조건 모두 약 80시간 이후에 정상상태에 도달하였다. 체류시간 3시간에서 유입수내 endosulfan 농도를 50mg/L 및 100mg/L로 증가시킨 결과, 제거효율이 각각 70% 및 50% 부근까지 저하되었다. 유입수의 pH를 4.0과 9.0으로 변화시켜 실험한 결과 각각 73%와 66%의 제거효율을 나타내었다. pH 9.0보다 4.0에서 제거효율이 약간 높은 이유는 사용 배지의 pH가 약산성을 띠기 때문에 알칼리 상태보다 약산성에서 미생물의 활성이 높기 때문으로 판단된다. 유출수를 재순환 시킨 결과 제거효율이 90%까지 향상되는 것을 볼 수 있었으며, 이는 재 순환되는 유출수의 농도 저감 및 고정화 미생물과의 재 접촉에 기인하는 것으로 판단된다. 유입수에 공기를 주입한 결과, 유출수의 재순환 없이도 약 40시간 후에 93%의 제거효율을 보였으며 이는 미생물 활성의 증가에 기인하는 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1644-1648
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• 2008

해안지역은 해수욕, 어패류의 수집 등의 각종 레크레이션에 있어 많은 사람들이 이용하는 공간이며, 해수는 해안지역에서 각종 활동 중 섭취할 가능성이 있으므로, 수질이 매우 중요하다고 할 수 있다. 이에 본 연구에서는 실제 해수욕장의 수치 모의(수리, 수문, 수질)를 통하여 우수 및 오수가 지표를 통해 해안으로 유입될 경우의 해안지역의 수질에의 영향에 관하여 연구하였다. 지표에서의 우수 유출 및 오수의 흐름을 수치해석은 MOUSE 모델을 사용하였으며 해안지역의 수치해석은 MIKE 3 모델을 사용하였다. 또한 수질 분석을 위하여 미생물의 증감에 영향을 주는 해당 지역의 기온, 수온, 일조량 등의 각종 인자를 구성하여 MIKE 3의 ECOLAB 모듈을 통하여 생물학적 분석을 수행하였다. 그 결과, 해수의 오염이 발생하면, 해수욕이 가능한 기간을 위주로 확인하였을 시, 미생물이 해수에 존재하는 시간은 연간 총 200시간 가량인 것으로 나타났으며, 강우시 해수의 오염이 발생할 시, 강우가 그친 뒤에도 미생물이 완전히 사멸할 때 까지 $4{\sim}6$시간의 정화기간이 필요한 것으로 나타났다. 그리고 첨두 오염 부하량은 비가 그친 직후에 나타나는 것으로 나타났으며 미생물의 해수 유입은 5mm 이상의 강우일 경우에 기준치 이상의 미생물이 발생하며, 해당 지역에 합류식 하수관거가 있을 시에 더욱 많이 발생하는 것으로 나타났다.

• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.169-177
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• 2005

This study focuses on investigating roles of microorganisms in decontamination of reed rhizosphere in Sunchon Bay, Korea, which is considered one of the marsh and mud environment severely affected by human activities such as agriculture and fisheries. In general, the bay is known to play the role of the buffering zone to reduce the sudden impact or change by environmental stresses. In our initial efforts to elucidate the microbial functions in decontamination process in reed rhizosphere, pure bacteria capable of degrading aromatic hydrocarbons were isolated from reed (Phragmites communis) rhizosphere of Sunchon bay by enrichment culture using either benzene, toluene, ethylbenzene, or xylene (BTEX) as a sole source of carbon and energy. Measurement of the rates of BTEX degradation and cell growth during the incubation in BTEX media under several temperature conditions demonstrated maximized degradation of BTEX at $37^{\circ}C$ in both strains. Both strains were also resistant to all the heavy metals and antibiotics tested in this study, as well as they grew well at $42^{\circ}C$. Identification of the isolates based on 16S rRNA gene sequences, and a variety of phenotypic and morphologic properties revealed that the two strains capable of BTEX catabolism were among Microbacterium sp., and Rhodococcus sp. with over $95{\%}$ confidence, designated Microbacterium sp. EMB-1 and Rhodococcus sp. EMB-2, respectively This result suggested that in the rhizosphere of reed, one of major salt marsh plants they might play an important roles in decontamination process of reed rhizosphere contaminated with petroleum such as BTEX.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.150-157
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• 2007

The advanced bioremediation of diesel-contaminated soil through the exploration of bacterial interaction with plants was studied. A diesel-degrading rhizobacterium, Rhodococcus sp.412, and a plant species, Zea mays, having tolerant against diesel was selected. Zea mays was seeded in uncontaminated soil or diesel-contaminated soil with or without Rhodococcus sp. 412. After cultivating for 30 days, the growth of Zea mays in the contaminated soil inoculated with Rhodococcus sp. 412 was better than that in the contaminated soil without the bacterium. The residual diesel concentrations were lowered by seeding Zea mays or inoculating Rhodococctis sp. 412. These results Indicate that the simultaneous use of Zea mays and Rhodococcus sp. 412 can give beneficial effect to the remediation of oil-contaminated soil. Bacterial community was characterized using a 16S rDNA PCR and denaturing gradient gel electrophoresis (DGGE) fingerprinting method. The similarities of DGGE fingerprints were $20.8{\sim}39.9%$ between the uncontaminated soil and diesel contaminated soil. The similarities of DGGE fingerprints were $21.9%{\sim}53.6%$ between the uncontaminated soil samples, and $31.6%{\sim}50.0%$ between the diesel-contaminated soil samples. This results indicated that the structure of bacterial community was significantly influence by diesel contamination.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.105-119
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• 2012

Indigenous bacteria isolated from contaminated sites play important roles to remediate contaminated groundwater. Chromium has the most stable oxidation states. Cr(VI) is toxic, carcinogenic, and mobile, but Cr(III) is less toxic and immobile. In this study, indigenous microorganism (MMPH-0) was enriched from Cr(VI) contaminated groundwater, and identified by 16S rRNA gene analysis. Using MMPH-0, the effect of stimulating with e-donors (glucose, lactate, acetate, and no e-donor control), respiration conditions, biomass, tolerance, and geochemical changes on Cr(VI) reduction were investigated in batch experiments for 4 weeks. The changes of Cr(VI) concentration and geochemical conditions were monitored using UV-vis-spectrophotometer and Eh-pH meter. And the morphological and chemical characteristics of MMPH-0 and precipitates in the effluents were characterized by TEM-EDS and SEM-EDS analyses. MMPH-0 (Enterobacter aerogenes) was able to tolerate up to 2000 mg/L Cr(VI) and reduce Cr(VI) under aerobic and anaerobic conditions. MMPH-0 performed faster and higher efficiency of Cr(VI) reduction with electron donors (over 70% after 1 week with e-donor, 10-20% after 4 weeks without e-donor). The changes of Eh-pH in effluents showing the tendency from oxidizing to reducing condition and a bit of acidic change in pH due to microbial oxidation of organic matters donating electrons and protons suggested the roles of MMPH-0 on Cr(VI) in the contaminated water catalyzing to transit geochemical stable zone for more stable $Cr(OH)_3$ or Cr(III) precipitates. TEM/SEM-EDS analyses of MMPH-0 and precipitates indicate direct and indirect Cr(VI) reduction: extracellular polymers capturing Cr component outside cells. These results suggested diverse indigenous bacteria and their biogeochemical reactions might enhance more effective and feasible remediation technology of redox sensitive heavy metals in metal-contaminated in groundwater.

• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.113-117
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• 2017

Bioremediation is a technique using microorganisms to clean up contaminated pollutants including heavy metals. It is well known that yeasts have a high capacity to remove a wide range of metals by biosorption. Therefore, this study was focused on to obtain yeast mutant that has strong tolerance to zinc (Zn), one of representative heavy metals. The Zn resistant yeast mutant (ZnR) was induced and isolated by growing yeast cells in media containing 1 mM $ZnCl_2$ and gradually increasing the concentration until 80 mM $ZnCl_2$, in which cells were adapted and survived. The induced ZnR cells showed strong tolerance to Zn stress compared with control cells. Moreover, the ZnR cells showed increased tolerance to cadmium and nickel stress but decreased tolerance to copper stress. The increased tolerance of ZnR cells to Zn stress was due to mutation of genes. This study can be useful in bioremediation of heavy metals as the metal tolerant microorganism was artificially induced in short time.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.15-19
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• 2000

원유로 오염된 모래지역의 생물정화기술 적용을 위하여 인위적으로 오염시킨 해사를 이용한 타당성 연구를 수행함으로써, 오염 환경에 최적 적용방법을 검토하였다. 무기 영양염류, 인공계면활성제, 유류분해미생물의 적용성을 검토한 결과, 영양염류의 첨가가 효과적이며 외부로부터 미생물을 첨가할 경우 토착미생물보다 많은 양을 적용하는 것이 효과적임을 알 수 있었다. 계면활성제는 CMC와 동일 농도로 첨가할 때 높은 효과를 얻을 수 있었다 원유성분의 무기화에 의해 발생되는 이산화탄소량 측정이 타당성 평가의 유효한 도구임을 알 수 있었으며 미생물의 활성과 원유성분 변화로 이를 검증할 수 있었다.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2003.07a
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• pp.75-75
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• 2003

방향족 화합물인 폴리염화비페닐(PCB)은 비페닐 기본골격의 10개소의 탄소에 1개에서부터 10개까지의 염소가 치환되어 있는 물질로써 그 독성과 잔류성으로 인해 중대한 환경오염물질의 하나로 주목받고 있다. 폴리염화비페닐에 의한 환경오염은 수질오염으로 이어지며, 식물연쇄에 의해 어류의 경우 그 농축계수가 10만 정도까지 이른다고 한다. 이러한 현상은 육상에서도 일어나며 생물농축과 식물연쇄에 의해 결국 식품을 오염시키게 된다. 이와 같은 난분해성 오염물질의 정화에는 미생물이 가지고 있는 분해능력이 큰 역할을 담당한다는 것이 알려져 있다. 1970년대 토양으로부터 비페닐을 분해ㆍ이용할 수 있는 비페닐 자화성균이 단리된 이후, 호기적으로 폴리염화비페닐을 분해하는 균을 중심으로 연구가 행해져 왔으며 방향족 화합물에 있어서의 대사 경로 등이 밝혀지게 되었다. 본 연구에서는 폴리염화비페닐을 분해하는 능력을 가지는 분해균을 모델로 하여 다양한 환경하에서 폴리염화비페닐을 분해ㆍ대사 할 수 있는 미생물의 분리를 시도하였다. 그 결과 클로로비페닐 분해능을 가진 Gram 양성균을 단리하는데 성공하였고, 이 균이 Bacillus속의 미생물인 것을 확인하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.704-708
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• 2006

This study was designed to investigate the effect of Fenton reaction and consecutive rhizosphere biodegradation on diesel-contaminated soil. According to the result, the TPH removal rate was increased with the concentration of hydrogen peroxide in Fenton's treatment and showed 83.5% for soybean, 81.5% for rice, and 76% for control in rhizosphere biodegradation.