• 한국지반공학회논문집
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• 제27권5호
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• pp.75-84
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• 2011

흙 속에 존재하는 미생물 중에는 탄산칼슘과 같은 광물질을 생성시키는 미생물이 있으며, 이렇게 생성된 탄산칼슘은 지반 내의 공극에 침전되어 수밀성을 높이거나 지반을 고결시킬 수 있다. 본 연구에서는 이와 같은 미생물이 지반 내에서 광물질을 어느 정도 생성하는지와 생성된 광물질이 지반의 강도에 어떤 영향을 미치는지 분석하였다. 현장지반의 약한 고결상태를 모사하기 위하여 모래에 3%의 시멘트를 섞어 3일 동안 양생시킨 원형공시체를 제작하였다. 약하게 고결된 공시체에 Sporosarcina pasteurii 균 용액을 20일 동안 최대 10회 반복 주입한 다음 공시체의 일축압축강도와 공극을 채운 광물질을 분석하였다. 미생물을 1회 주입한 경우 공시체의 일축압축강도는 미생물이 들어가지 않은 경우보다 5% 정도 증가하였으나, 2회 이상 주입할 경우 강도는 오히려 감소하였으며 주입 횟수가 증가할수록 일축압축강도는 계속 감소하여 최대 50%까지 감소하였다. 미생물을 반복 주입할 경우 주입 횟수에 따라 고결모래 내에 탄산칼슘이 지속적으로 생성되면서 공극을 채우는 정도가 증가하였다. 하지만, 약하게 고결된 지반 내에 탄산칼슘이 일정 이상 침전될 경우 강도는 오히려 감소하였다.

• 한국토양비료학회지
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• 제50권2호
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• pp.71-80
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• 2017

This study was conducted to investigate the application effect of Lysobacter antibioticus HS124 (gelatinase and chitinase producing microorganism; GCM) for the improvement of soybean yield and control of stink bug. Our results showed that the yield of GCM-treated soybean increased by 17.0, 20.3, 19.0, and 25.6% in the experimental field sites of Muan-gun, Sunchang-gun, Gwangju 1, and Gwangju 2, respectively, compared to the yield of the soybean obtained by conventional practice treatment (CPT); however in the Gimjae-si, the yield decreased by 10.6%. Results in both pods and seeds $plant^{-1}$ were significantly increased in Gwangju 2 by the GCM cultured broth treatment (GCMT). Ratio of 3 seeds $pod^{-1}$ in Sunchang-gun was statistically significant between GCMT and CPT, however, the result in the other field showed no significance. Germination rate was only statistically improved by GCMT in Gwangju 2 field site. GCMT reduced the appearance of stink bug in all experimental field sites except in Gimjae-si. The soybean seed damage by stink bug was no significance in all of treatments. Therefore, GCMT could improve the productivity of soybean and also control the infestation of stink bug.

• 한국토양비료학회지
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• 제45권3호
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• pp.410-420
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• 2012

The heavy reliance on fossil fuels, especially oil and gas has triggered the global energy crisis. Continued use of petroleum fuels is now widely recognized as unsustainable because of their depleting supplies and degradation to the environment. To become less dependent on fossil fuels, current world is shifting paradigm in energy by developing alternative energy sources mainly through the utilization of renewable energy sources. In particular, bioenergy recovery from wastes with the help of microorganism is viewed as one of the promising ways to mitigate the current global warming crisis as well as to supply global energy. It has been proved that microorganism can generate power by converting organic matter into electricity using microbial fuel cells (MFCs). MFC is a bioelectrochemical device that employs microbes to generate electricity from bio-convertible substrate such as wastewaters including municipal solid waste, industrial, agriculture wastes, and sewage. Sustainability, carbon neutral and generation of renewable energy are some of the major features of MFCs. However, the MFC technology is confronted with a number of issues and challenges such as low power production, high electrode material cost and so on. This paper reviews the recent developments in MFC technology with due consideration of electrode materials used in MFCs. In addition, application of biocathodes in MFCs has been discussed.

• Advances in environmental research
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• 제9권3호
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• pp.215-232
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• 2020

Crude oils are essential source of energy. It is majorly found in geographical locations beneath the earth's surface and crude oil is the main factor for the economic developments in the world. Natural crude oil contains unrefined petroleum composed of hydrocarbons of various molecular weights and it contains other organic materials like aromatic compounds, sulphur compounds, and many other organic compounds. These hydrocarbons are rapidly getting degraded by biosurfactant producing microorganisms. The present study deals with the isolation, purification, and characterization of biosurfactant producing microorganism from oil-contaminated soil. The ability of the microorganism producing biosurfactant was investigated by well diffusion method, drop collapse test, emulsification test, oil displacement activity, and blue agar plate method. The isolate obtained from the oil contaminated soil was identified as Bacillus subtilis. The identification was done by microscopic examinations and further characterization was done by Biochemical tests and 16SrRNA gene sequencing. Purification of the biosurfactant was performed by simple liquid-liquid extraction, and characterization of extracted biosurfactants was done using Fourier transform infrared spectroscopy (FTIR). The degradation of crude oil upon treatment with the partially purified biosurfactant was analyzed by FTIR spectroscopy and Gas-chromatography mass spectroscopy (GC-MS).

• 한국미생물·생명공학회지
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• 제20권4호
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• pp.401-408
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• 1992

Cholesterol oxidase를 생산하는 균주를 토양으로 분리하고 이를 배양하여 효소를 생산한 후 정제하여 그 특성을 조사하였다. 본 효소는 CH2 concentrator에 의한 농축, DEAE-cellulose chromatography, Superose 12 column FPLC로 정제하였고, 비활성이 약 31배나 증가하였다. 이 효소는 $50^{\circ}C$, pH 6.0에서 최대 활성을 나타냈고 30-$45^{\circ}C$ 범위에서는 안정하였다. pH에 대한 안정성은 pH 6.0-11.0까지 광범위한 안정성을 보였으며, Km 값은 cholesterol에 대해서 $3.65{\times}10^{-3}$M이며 분자량은 59,500 dalton으로 추정 된다. 또한 $Ca^{2+}$, $Ba^{2+}$, $Fe^{2+}$, Brij 35에 의해서는 효소의 활성이 저해되지 않았지만, $Hg^{2+}$, $Ag^{2+}$ 및 SDS에 의해서는 저해되는 것으로 나타났다.

• 약학회지
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• 제40권6호
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• pp.713-719
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• 1996

Identification of soil microorganism strain B-6. a producer of acyl CoA synthetase inhibitor, based on its morphological, physiological, biochemical and chemotaxonomical charact eristics was performed. The strain B-6 was identified as Bacillus subtilis. Ihe acyl CoA synthetase inhibitor produced by this strain was highly achieved in fermentation medium that contained glucose 1.0%, soluble starch 1.0%, NH$_4$Cl 0.3%, oatmeal 1.0%, pharmamedia 1.0%, basic magnesium carbonate 0.5%. pH 7.5 at 30$^{\circ}$C for 7 days. The optimal pH and temperature for growth were 9.0 and 30$^{\circ}$C, respectively. Butanol extract of culture filterate of strain B-6 in acyl CoA synthetase inhibitor production medium containing corn steep liquor exhibited high acyl CoA synthetase inhibitor activity and antimicrobial activity against C. albicans. But chloroform extract of culture filterate of strain B-6 in medium containing NH$_4$Cl, ($NH_4)_2SO_4$ or urea instead of corn steep liquor exhibited higher antimicrobial activity against C. albicans than that of butanol extract.

• 한국환경농학회지
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• 제19권2호
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• pp.183-187
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• 2000

고농도 축산폐수의 과부하 고도처리를 위한 토양미생물을 이용한 공정개발 연구결과 질소${\cdot}$제거율은 97% 이었다. 질산화를 위한 최소 HRT는 11일 이었으며 이때의 SRT는 25일 이었다. HRT 5일에서 11일 사이에 도 질산화는 있었으나 이 때는 $NO_2-N$이 대부분으로 완전질산화를 달성하지는 못했다. pH와 $NO_2\;^--N$, $NH_3\;^--N$ 의 관계로부터 반응조는 nitrosomonas 저해영역에 속해 있었으나 약간의 pH 조절로 충분한 질산화를 달성할 수 있을 것으로 판단되었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권4호
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• pp.32-39
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• 2013

This research focused on the effects of heavy metals on the biomonitoring activity of genetically engineered bioluminescent bacteria, Pseudomonas putida mt-2 KG1206. KG1206 was exposed to single or binary mixtures of different heavy metals as well as soils contaminated with heavy metals. In case of single exposure with different inducer pollutant, the toxicity order was as followings : As(III) > Cd, As(V) >> Cu, Cr(VI). The toxic effects of the binary mixtures was compared to the expected effect based on a simple theory of probabilities. The interactive effects were mostly additive, while in few cases antgonistic and synergistic mode of action was observed for some concentration combinations. No considerable correlation was found between the total metal contents in soils and the bioluminescence activity of each sample. However, statistically significant differences (p = 0.0102) were observed between two groups, classified based on arsenite contamination. These results demonstrate the usage of recombinant bioluminescent microorganism in biomonitoring and the complex interactive effects of metals.

• 보존과학연구
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• 통권37호
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• pp.5-15
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• 2016

국내 목조문화재의 흰개미 피해는 토양과 인접한 건축물의 기둥하부에 주로 발생하지만 흰개미의 유입은 주변 야산의 부후된 목재나 수목 제거 후 남겨진 그루터기에 서식하는 흰개미가 인접한 건물로 유입되어 발생하게 된다. 본 연구는 목조문화재 생물피해 조사에서 흰개미 서식이 확인된 그루터기를 제거하면서 수거된 보은 법주사, 여수 흥국사, 그리고 보성 이용우 가옥의 그루터기와 주변 토양으로부터 미생물을 분리하였다. 그 결과, 세균의 분포 비율이 높았고 지역에 따라 세균 군집에 명확한 차이를 보였으며, 특히 보성 이용우 가옥 내 토양에서 다양한 세균이 다량 분포하는 것으로 나타났다.

• Journal of Species Research
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• 제9권4호
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• pp.339-345
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• 2020

The Earth contains billions of microbial species, although the vast majority cannot be cultured in laboratories and are thus considered unidentified and uncharacterized. Extremophiles are microorganisms that thrive in extreme conditions, including temperature, salinity, and pH. Extremophilic microorganisms have provided important insights for biological, metabolic, and evolutionary studies. Between 2017 and 2019, as part of a comprehensive investigation to identify bacterial species in Korea, eight bacterial strains were isolated from marine and non-marine environments in Jeju Island. These strains were cultured under extreme salinity or pH conditions. Phylogenetic analysis using 16S ribosomal RNA(rRNA) gene sequencing indicated that all eight strains belonged to the phyla Gammaproteobacteria, Bacilli, and Alphaproteobacteria. Based on their high 16S rRNA gene sequence similarities(>98.7%) and the formation of strong monophyletic clades with their closest related species, all isolated strains were considered as an unrecorded strain, previously unidentified species. Gram stain reaction, culture conditions, colony and cell morphology, biochemical characteristics, isolation source, and National Institute of Biological Resources(NIBR) IDs are described in this article. The characterization of these unrecorded strains provides information on microorganisms living in Korea.