• 한국미생물·생명공학회지
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• 제26권5호
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• pp.465-469
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• 1998

본 연구의 목적은 토양매립조건에서 생분해성 고분자의 생분해도를 정량적이며 신속하게 측정하는 방법을 개발하는 것으로서, 실험대상 물질은 생분해가 잘되는 것으로 알려져 있는 셀로판 필름을 사용하였다. 분해정도를 측정하기 위하여 흙속에서 채취한 셀로판 필름을 HCl로 가수분해 시킨 후 생성된 glucose를 측정하는 방법을 사용하였다. 토양매립시 생분해도는 겨울에는 4개월간 고작해야 41.2%정도의 분해를 보였으나, 여름에는 2개월동안 76.5%정도의 분해도를 나타낸 결과로 보아 계절의 영향을 많이 받는 것으로 나타났다. 실험실적 토양매립조건의 실험을 위해 토양을 채취하여 플라스크에 넣고, 여기에 셀로판 필름을 묻은 후 항온배양기내에서 일정한 조건(3$0^{\circ}C$, 습도 50~55%)으로 실험하였다. 이때에는 40일 경과 후 94%정도의 분해도를 나타내었다. 분해속도는 1차 반응 속도식을 따르고 반응속도 상수는 067(1/day)이었다. 생분해도의 가속화를 위해 토양내 미생물을 필름 표면에 접종하고 플라스크 내의 흙속에 매립한 후 항온배양기내에서 생분해도를 측정한 결과, 초반 12일경까지는 미생물 접종의 효과가 뚜렷이 나타났으나 말기로 갈수록 그 효과는 없어졌다. 가속화를 위한 또 다른 방법으로 토양내 영양성분인 N, P, S 등을 추가로 공급한 결과, 초반부터 말기까지 지속적인 가속화 효과를 보임과 동시에 반응속도 상수도 0.096(1/day)에서 0.21(1/day)로 118%정도의 높은 증가를 보였다. 결과적으로, 실외에서의 토양매립조건에서는 생분해도의 반응속도 상수가 겨울기간의 0.0042(1/day), 여름기간의 0.024(1/day)로 나타났고 같은 실험실적 토양매립조건에서라도 토양을 채취한 시기에 따라 봄에 채취한 토양에서는 0.065(1/day)로 여름에 채취한 토양에서는 0.096(1/day)로 반응 속도 상수가 다르게 나타났다. 각각의 매립조건들 중에서 N, P, S 모두를 첨가한 실험실적 토양매립조건에서의 생분해도가 가장 뛰어난 것으로 나타났다.

• 한국환경보건학회지
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• 제25권3호
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• pp.36-43
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• 1999

The present study was performed to investigate biodegradation rate of dichlorvos and methidathion. In the biodegradation test of two pesticides by the modified river die-away method from June 17 to August 22, 1998, the biodegradation rate constants and half-life were determined in Nakdong(A) and Kumho River(B). Biodegradation rate of dichlorvos was 4.51% in A sampling point, 6.88% in B sampling point after 7 days. Biodegradation rate constants and half-life of dichlorvos were 0.0066 and 105 days in A sampling point, 0.0102 and 67.9 days in B sampling point, respectively. Biodegradation rate of methidathion was 23% in A sampling point, 36% in B sampling point after 7 days. Biodegradation rate constants and half-life of methidathion were 0.0377 and 18.4 days in A sampling point, 0.0641 and 10.8 days in B sampling point, respectively. Biodegradation rate of methidathion was faster than that of dichlorvos. This suggested that the difference in biodegradation of pesticides was due to difference in the water quality and standard plate counts in the Nackdong and Kumho Rivers. The result of correlation analysis between biodegradation rate constants of the pesticides and water quality(DO, BOD, SS, ABS, NH$_3$-N, and NO$_3$-N) showed significant correlation with BOD, SS and NH$_3$-N at the 5% significant level. A significant linear equation was obtained from regression analysis at the 5% significant level, whereas, dependent variables were BOD, SS and NH$_3$-N, and the biodegradation rate constant was independent variable. It is suggested that dichlorvos will be mainly degraded by hydrolysis, and for methidathion was both hydrolysis and biodegradation. A significant QSAR equation was obtained from regression analysis at the 10% significant level, whereas, dependent variable is biodegradation rate constants of BPMC, chlorothalonil, dichlorvos and methidathion, vapor pressures, partition coefficients and water solubilities of the pesticides are independent variables. Also, a significant linear equation was obtained from regression analysis at the 1% significant level, whereas, dependent variable is biodegradation rate constants of BPMC, chlorothalonil, dichlorvos and methidathion, hydrolysis rate constants of the pesticides are independent variables. It is suggested that the pesticides will be degraded by main degradation factor when the pesticides was affected both hydrolysis and biodegradation.

• 한국환경보건학회지
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• 제21권4호
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• pp.37-43
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• 1995

The course of biodegradation of anionic surfactants, Linear Alkylbenzene Sulfonates(LAS), Sodium Lauryl Ethoxylate Sulfonate(SLES), and Sodium Lauryl Sulfonates(SLS), which are mainly used to make detergents and shampoo, was investigated. The degree of biodegradation was studied as a function of concentration, volumetric flow rate, and temperature in Naktong River. MethyleneBlue Active Substances(MBAS), Total Dissolved Organic Carbon(TOC), and Chemical Oxygen Demand(COD) were measured to evaluate the degree of biodegradation. The degree of biodegradation of LAS was highly dependent upon the concentration and was increased as the concentration was decreased and that of SLES and SLS was almost constant at the concentration of less than 200 ppm, but was much increased as the volumetric flow rate was increased or the temperature was increased.

• 한국식품위생안전성학회지
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• 제14권3호
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• pp.249-254
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• 1999

Modified river die-away 법으로 1998년 6월 17일부터 7월 22일 까지 낙동강(A)과 금호강(B)에서 채수한 강물로 BPMC와 chlorothalonii의 생분해 시험을 한 결과는 다음곽 kx다. BPMC의 경우 A지점의 실험군에서는 배양 7일 경과후 27%의 생분해를 나타냈으며 B지점의 실험군에서는 배양 7일 경과 후 40%의 생분해를 나타냈다. 생분해 속도상수와 반감기는 A지점에서 0.0460 및 15.1일 이었고, B지점에서 0.0749 및 9.3일로 조사되었다. Cholorothalonii의 경우 A지점의 실험군과 B지점의 실험군에서 배양 24시간 경과 후 모두 100%의 빠른 생분해를 나타내었다. 생분해속도상수와 반감기는 A지점에서 0.1416 및 4.9시간이었고, B지점에서 0.1803 및 3.8시간으로 조사되었다. Chlorothalonil이 BPMC보다 생분해속도가 빨랐으며, 수질오염이 심한 지역일수록 생분해율이 높은 것은 두 지점의 수질오염 및 종속영양세균수의 차이가 영향을 미치는 것으로 추정된다. 두 가지 농약의 생분해속도와 실험수의 DO, BOD, SS, ABS, $NH_3-N$와의 상관성을 구한 결과 각각 5% 유의수준에서 PMC의 경우 BOD, SS 및 $NH_3-N$이었고 chlorothalnil의 경우 SS, BOD 및 $NH_3-N$를 독립변수로, 생분해속도를 종속변수로 회귀분석을 실시한 결과는 5% 유의수준에서 각각의 농약에 대해 유의한 회귀식을 구할 수 있었다. BPMC는 실제 환경 중에서 생분해에 의한 영향을 더 받을 것으로 생각되며 chlorothalonil은 주요한 분해경로가 생분해인 것을 알 수 있었다.

• 상하수도학회지
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• 제11권4호
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• pp.54-62
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• 1997

Disposal of blue crab wastes represents a significant problem to processors, who are limited with respect to acceptable disposal alternatives. Anaerobic bioconversion technology was investigated to determine an environmentally sound and economic disposal method for these wastes. In the study ultimate methane yield for total crab solid waste was $0.180m^3/kg$ VS added and biodegradation rate constant was $0.15day^{-1}$. Methane yield of the bench-scale reactor operated on similar feedstock was $0.189m^3/kg$ VS added and biodegradation rate constant was $0.06day^{-1}$. These results indicate that anaerobic bioconversion of blue crab wastes was technically feasible. Use of anaerobic bioconversion technology can be an attractive option for blue crab processing waste management. The by-product methane gas could be used for maintainign a number of processing operations (i.e., heat for cooking, or keeping temperature of digester constant).

• Journal of Microbiology and Biotechnology
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• 제12권4호
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• pp.695-698
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• 2002

The biodegradation of 2,4,6-trinitrotoluene (TNT) was performed on a laboratory scale using P. putida originally isolated from explosive-contaminated soil. One hundred mg/1 of TNT was completely degraded within 20 h under optimum conditions. Various supplemental energy sources (carbon sources, nitrogen sources, and surfactant) were tested, with the main objective of identifying an inexpensive source and enhancing the degradation rate for large-scale biodegradation. Based on the degradation rate, molasses was selected as a possible supplemental carbon source, along with NH$_4$Cl and Tween 80 as a nitrogen source and surfactant, respectively. The degradation rate increased about 3.3 fo1d when supplemental energy sources were added and the degradation rate constant increased from 0.068 h$\^$-1/ to 0.224 h$\^$-1/. These results appear to be promising in application of the process to TNT-contaminated soil applications.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.235-238
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• 2001

Monod kinetics에 관련된 주요 생분해 파라미터를 도출하기 위하여 microcosm 규모의 배치실험에서 BTEX 화합물에 대해 분해능이 우수한 Pseudomonas aeruginosa을 이용해 다양한 농도의 벤젠에 대한 분해기작을 고찰하였다. 벤젠의 생분해율(D)과 Maximumspecific growth rate ($\mu$$_{max}$)는 기질의 농도가 증가할수록 높아지다가 최고점에 도달 후에 점차적으로 감소하였으며 이것은 어느 한계점 이상의 벤젠 농도가 미생물의 생분해에 방해 요소로 작용한다는 것을 나타낸다. 그러나 미생물에 의한 벤젠 분해의 상관관계를 나타내는 yield coefficient(Y)는 벤젠의 초기 농도가 낮을수록 높은 값을 나타내었다. Microbial decay constant( b)와 half-saturation constant(K$_{c}$)는 각각 0.21~0.48day$^{-1}$와 218mg/$\ell$로서 문헌값 보다 높은 수치를 나타내었다. 실험으로부터 결정된 생분해 파라미터들은 초기 벤젠 농도에 따라 큰 차이를 보이므로 생분해 모델링에 사용할 파라미터는 기질농도에 따라 적절하게 선택되어야 한다고 사료된다.

• 한국환경보건학회지
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• 제23권3호
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• pp.85-90
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• 1997

The objective of this study was to investigate biodegradation of TPA(terephthalic acid) and EG (ethylene glycol), treatment efficiency of polyester weight loss wastewater and microbial characteristics by aerated submerged biolfilm(ASB) p.rocess. In a batch reactor, pH increased from 7.0 to 8. 5 in the biodegradation of TPA. Whereas, in case of EG, decreased from 7.0 to 5.2. COD concentration rapidly decreased within 24hr in the biodegradation of TPA and EG. COD removal velocity constant(k) were 0.065-0.088 hr$^{-1}$. The biodegradation velocity of TPA was 1.4 times faster than that of EG. The ratio of suspended biomass to the total biomass in the reactor was 18.3-33.3%, increased as a high ratio of EG content. Biofilm thickness, biofilm dry density and attached biomass were 346-432 $\mu$m, 41.8-61.9 mg/cm$^3$, 1.45-2.67 mg/cm$^2$, respectively. There values increased as a high ratio of TPA content. In the hydraulic retention time of 36 hr, organic loading rate of 4 kgCOD/m$^3\cdot$ day and packing ratio of 70%, the effluent concentrations of TCOD, SCOD in a continuous flow reator were 1,388 mg/l, 147 mg/l and removal efficiencies were 77%, 97.6%, respectively.

• 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 $poly-{\beta}-hydroxybutyrate$.

• 한국환경과학회지
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• 제31권3호
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• pp.227-235
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• 2022

In this study, a biodegradation model of based on molecular cellulose was established. It is a mathematical, kinetic model, assuming that two major enzymes randomly break glycosidic bonds of cellulose molecules, and calculates the number of molecules by applying the corresponding probability and degradation reaction coefficients. Model calculations considered enzyme dose, cellulose chain length, and reaction rate constant ratio. Degradation increased almost by two folds with increase of temperature (5℃→25℃). The change of degradation was not significant over the higher temperatures. As temperature increased, the degradation rate of the molecules increased along with higher production of shorter chain molecules. As the reaction rates of the two enzymes were comparative the degree of degradation for any combinations of enzyme application was not affected much. Enzyme dose was also tested through experiment. While enzyme dose ranged from 1 mg/L to 10 mg/L, the gap between real data and model calculations was trivial. However, at higher dose of those enzymes (>15 mg/L), the experimental result showed the lower concentrations of reductive sugar than the corresponding model calculation did. We determined that the optimal enzyme dose for maximum generation of reductive sugar was 10 mg/L.