• 대한토목학회논문집
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• 제26권4B호
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• pp.433-437
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• 2006

최근, 활성 슬러지 공법에 대한 수학적 모델링은 폐수처리장의 설계와 운영에 있어서 매우 중요한 인자로 인식되고 있다. 그럼에도 불구하고, BNR 공정에서 미생물의 성장 및 호흡과 관련한 내 외부 기질의 이용 경로에 관한 정보는 여전히 부족한 실정이다. 본 논문에서는 ASM No.3와 비교되는 새로운 개념의 활성슬러지 모델을 제시하고자 한다. 미생물의 단계별 성장이론에 근거한 이 모텔의 구조는 호기성 저장, 내부저장물질(ISCs; Intercellular Storage Compounds)과 외부기질 활용에 따른 미생물의 성장, 내생호흡과 내부저장물질을 이용한 호기성 호흡 등 5 단계로 구성되어 있다. 단계적 성장모델에 기초한 예측결과는 산소이용율(OUR)과 TCOD에 의한 실험결과에 있어 ASM No.3의 결과보다 더욱 일치함을 나타냈다.

• The Korean Journal of Ecology
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• 제21권3호
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• pp.277-282
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• 1998

The microbial degradation of $poly-{\beta}-hydroxybutyrate$ (PHB) films was studied in soil microco는 incubated at a constant temperature of 2, 10, 20, 30 and $40^{\circ}C$ for up to 49 days. The degradation rate measured through loss of weight was enhanced by incubation at a higher temperature. At the soil temperature $40^{\circ}C$, $poly-{\beta}-hydroxybutyrate$ was rapidly degraded at a decay rate of 3.5% weight loss per day. The degradation of $poly-{\beta}-hydroxybutyrate$ did not affected significantly the chemical properties of soils such as pH and electric conductivity. However, microbial activity of soil in terms of dehydrogenase activity was increased by the degradation of $poly-{\beta}-hydroxybutyrate$.

• 한국토양비료학회지
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• 제49권2호
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• pp.144-156
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• 2016

Soil is a dynamic biological system, in which it is difficult to determine the composition of microbial communities. Knowledge of microbial diversity and function in soils are limited because of the taxonomic and methodological limitations associated with studying the organisms. In this review, approaches to measure microbial diversity in soil were discussed. Research on soil microbes can be categorized as structural diversity, functional diversity and genetic diversity studies, and these include cultivation based and cultivation independent methods. Cultivation independent technique to evaluate soil structural diversity include different techniques such as Phospholipid Fatty Acids (PLFA) and Fatty Acid Methyl Ester (FAME) analysis. Carbon source utilization pattern of soil microorganisms by Community Level Physiological Profiling (CLPP), catabolic responses by Substrate Induced Respiration technique (SIR) and soil microbial enzyme activities are discussed. Genetic diversity of soil microorganisms using molecular techniques such as 16S rDNA analysis Denaturing Gradient Gel Electrophoresis (DGGE) / Temperature Gradient Gel Electrophoresis (TGGE), Terminal Restriction Fragment Length Polymorphism (T-RFLP), Single Strand Conformation Polymorphism (SSCP), Restriction Fragment Length Polymorphism (RFLP) / Amplified Ribosomal DNA Restriction Analysis (ARDRA) and Ribosomal Intergenic Spacer Analysis (RISA) are also discussed. The chapter ends with a final conclusion on the advantages and disadvantages of different techniques and advances in molecular techniques to study the soil microbial diversity.

• Journal of Ecology and Environment
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• 제44권2호
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• pp.72-80
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• 2020

Background: Antibiotics are widely used to treat animals from infections. After fertilizing, antibacterials can remain in the soil while adversely affecting the soil microorganisms. The concentration of oxytetracycline (OTC) in the soil and its effect on the soil microbial community was assessed. To assess the impact of OTC on the soil microbial community, it was added to the soil at concentrations of 50, 150, and 300 mg kg^-1 and incubated for 35 days. Results: The concentration of OTC added to the soil decreased from 150 to 7.6 mg kg^-1 during 30 days of incubation, as revealed by LC-MS. The deviations from the control values in the level of substrate-induced respiration on the 5th day of the experiment were, on average, 26, 68, and 90%, with OTC concentrations at 50, 150, and 300 mg kg^-1, respectively. In samples with 150 and 300 mg kg^-1 of OTC, the number of bacteria from the 3rd to 14th day was 2-3 orders of magnitude lower than in the control. The addition of OTC did not affect the fungal counts in samples except on the 7th and 14th days for the 150 and 300 mg kg^-1 contaminated samples. Genes tet(M) and tet(X) were found in samples containing 50, 150, and 300 mg kg^-1 OTC, with no significant differences in the number of copies of tet(M) and tet(X) genes from the OTC concentration. Conclusions: Our results showed that even after a decrease in antibiotic availability, its influence on the soil microbial community remains.

• 대한환경공학회지
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• 제33권9호
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• pp.630-635
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• 2011

본 연구는 급속 OUR (Oxygen Uptake Rate)방법의 영향인자 평가로서 최적의 미생물 활성도에 미치는 영향인자를 평가하는 실험을 진행하였으며, 실폐수를 이용하여 OUR변화에 따른 SCOD의 변화를 비교 평가하였다. 그 결과 최적의 F/M비는 0.03~0.05이었고, pH는 6.0~8.5, 온도는 $20{\sim}30^{\circ}C$에서 OUR 값이 가장 높았으며, 질산화에 대한 산소소모는 미비했다. OUR 변화에 따른 SCOD (Soluble COD)의 변화는 OUR 변곡점 시간 전후로 SCOD의 분해속도에 차이가 있음을 알 수 있었다. 본 연구의 실험방법을 이용하여 하수처리장의 유입수 실시간 예측을 통해 최적의 운영을 할 수 있을 것이라 기대한다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권1호
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• pp.7-18
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• 2015

The characteristics of As and heavy metals depend on the oxidation/reduction condition of the soil environment. The most heavy metals are immobilized by the reduction condition whereas As, Fe and Mn become more soluble. Therefore this study estimated the stabilization efficiency of the agricultural paddy soil in the vicinity of the abandoned mine using a flooded column test including analysis of the soil solution, contaminants fractionation and rice grain. Limestone and steelmaking slag were used as amendments for stabilization of the contaminated soil. In an analysis of the soil solution, the mobile characteristics of Fe and Mn, which were used as electron acceptors of the microorganisms, were controlled by increasing the pH by adding alkali amendments. This means that the contaminants combined with Fe and Mn can be stable under flooded reduction condition. However, the concentrations of cationic heavy metals (Cd, Pb, and Zn) were also decreased without amendments because the carbonates produced from microbial respiration increased the pH of the soil solution. In the amended soil, the specific sorbed fraction of As and carbonates fraction of heavy metals were increased when compared to the control soil at the end of the column test. Especially in heavy metals, the increase of carbonates fraction seems to be influenced by alkali amendments rather than microbial respiration. Because of the stabilization effect in the flooded paddy soil, the contents of As and Zn in rice grain from amended soil were lower than that of the control soil. But additional research is needed because of the relatively higher Pb content identified in the rice grain from the amended.

• 생명과학회지
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• 제20권9호
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• pp.1353-1357
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• 2010

공주 근교의 일본잎갈나무 조림지에서 벌목이 이루어지지 않은 비벌목지를 대조구, 벌목이 이루어진 벌목지를 처리구로 설정하여 토양호흡과 호흡에 영향을 주는 토양온도, 토양수분을 2008년 5월부터 12월까지 2주 간격으로 측정하였다. 조사기간 동안 대조구와 처리구의 평균 토양온도는 각각 $23.3{\pm}0.5^{\circ}C$, $25.9{\pm}3.1^{\circ}C$으로 처리구에서 높았으며, 토양수분은 각각 $27.76{\pm}7.12%$, $24.55{\pm}5.12%$으로 처리구에서 낮게 나타났다. 토양호흡량은 봄부터 하절기로 이행함에 따라 증가한 후 동절기에 이르기까지 감소하는 경향을 보였으며, 토양호흡과 토양온도와는 높은 상관관계($R^2$=0.8747)가 있었으나, 토양수분과는 유의성이 높지 않았다($R^2$=0.4437). 토양호흡량은 대조구와 처리구에서 모두 8월에 가장 높았으며, 이때 대조구와 처리구의 평균 토양호흡량은 각각 $0.82{\pm}0.13$, $1.32{\pm}0.10$ $CO_2g{\cdot}m^{-2}{\cdot}hr^{-1}$으로 나타났다. 대조구와 처리구에서 5월부터 12월까지 측정된 전체 호흡량은 각각 2,419.2, 3,610.8 $CO_2g{\cdot}m^{-2}$으로 대조구에 비해 처리구에서 49.3% 높은 것으로 나타났다. 본 연구의 결과 인위적인 삼림의 벌목은 토양 호흡량을 증가시켜 대기 중의 이산화탄소를 증가시킬 것으로 판단된다.

• Journal of Ecology and Environment
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• 제33권4호
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• pp.317-323
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• 2010

Nutrient availability is a critical component of agroecosystems, and is relevant to both above- and below- ground interactions. The principal objective of this study was to determine how the cessation of fertilization affects the communities of weeds and soil organisms in a corn/wheat field. Changes in dominant weed species, substrate-induced respiration, and the population density of nematodes and microarthropods were evaluated. Microbial substrate-induced respiration (SIR) and the population density of microarthropods decreased following the cessation of fertilization and were partly correlated with the aboveground weed biomass. The cessation of organic fertilizer application but continuing application of inorganic fertilizer reduced the population density of nematodes. In response to the cessation of fertilization, weed communities were dominated by species with little dependency on fertilization. Amaranthus retroflexus was identified as the most dominant species in the corn field; however, it was replaced by Digitaria ciliaris after the cessation of fertilization. In the wheat field, the cessation of fertilization led to a rapid reduction in the biomass of most weeds, except for Vicia angustifolia, supposedly as the result of symbiotic nitrogen fixation. Additionally, the fact that weed biomass was partially correlated with SIR or the population density of microarthropods may reflect a mutual feedback between soil organisms and weeds. The results indicate that the cessation of fertilization alters communities of weeds and soil organisms through changes in weed biomass and interactions with symbiotic microorganisms.

• 미생물학회지
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• 제31권1호
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• pp.93-98
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• 1993

수계생태계에서 유기물질의 순환을 이해하기 위하여 팔당호에서 종속영양 활성도와 세균세포의 효소활성의 계절절 변화를 연구하였다. 팔당호 I 의 glucose 전환시간은 수층, 퇴적토에서 2-1,300 시간, 17-170 시간, protein hydrolysate 는 5-900 시간, 15-240 시간, acetic acid 는 4-350 시간, 15-230 시간으로 계절적인 변화를 나타냈다. Glucose, protein hydrolysate, acetate 각각의 호흡율은 수층에서 23-32%, 38-41%, 22-28%로 나타났고 퇴적토에서는 34%, 61% and 41% 로 나타났다. 이 결과로 3가지 유기물질 종류 모두가 수층보다 퇴적토에서는 높은 율로 호흡됨을 알 수 있었다. 한편 세균의 $\alpha$-glucosidase, $\beta$-glucosidase, N-acetyl-$\beta$-D-glucosaminidase, aminopeptidase 활성력을 살펴본 결과 수층에서는 효소 각각에 대해 32-44%, 31-32%, 18-34% 61-67% 의 범위를 나타내었고 퇴적토에서는 34%, 40%, 23% 65%로 나타났다.

• 한국환경생태학회지
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• 제27권5호
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• pp.561-570
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• 2013

월악산국립공원 송계계곡에 발달되어 있는 소나무림에서 2011년 5월부터 2012년 4월까지 지상부와 지하부 생물량, 낙엽생산량, 낙엽층의 낙엽량, 그리고 토양의 유기탄소 분포를 조사하였으며, 탄소수지를 파악하기 위해 토양호흡량을 측정하였다. 지상부와 지하부 생물량에 분포되어 있는 유기탄소량은 각각 52.25, 14.52 ton C $ha^{-1}$ 이었으며, 낙엽층과 토양의 유기탄소량은 각각 4.71 ton C $ha^{-1}$, 58.56 ton C $ha^{-1}$ 50cm-$depth^{-1}$ 로 조사되었다. 조사지 소나무림의 전체 유기탄소량은 130.04 ton C $ha^{-1}$ 이었으며, 이중 51.4%가 식물체에 분포하는 것으로 나타났다. 본 소나무림에서 연간 광합성을 통하여 식물체에 고정된 유기탄소량은 4.26 ton C $ha^{-1}yr^{-1}$이었고, 층위별로는 교목층, 관목층, 초본층에 각각 4.12, 0.10 및 0.04 ton C $ha^{-1}yr^{-1}$의 유기탄소가 고정되었다. 조사기간 동안 낙엽생산을 통해 임상으로 유입되는 유기탄소량은 1.62 ton C $ha^{-1}$ 이었으며, 토양호흡을 통하여 방출되는 탄소량은 6.25 ton C $ha^{-1}yr^{-1}$으로 이중 미생물호흡과 뿌리호흡을 통해 방출되는 탄소량은 각각 3.19, 3.06 ton C $ha^{-1}yr^{-1}$이었다. 유기탄소 순 생산량과 미생물호흡량의 차이로 추정했을 때 본 소나무림에서 연간 대기로부터 순 흡수하는 유기탄소는 1.07 ton C $ha^{-1}yr^{-1}$ 로 조사되었다.