• 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.

• 한국환경과학회지
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• 제5권1호
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• pp.83-91
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• 1996

A recycling soap was prepared from non-cooking oils. The effects of physlcal and chemical properties of the recycling soap on biodegradation are expected to be different due to the thermal histories of the non-cooking oils. Therefore, the biodegradation rate of the recycling soap was studied by using Klebssella Pneumoniae(K. pneumoniae), and the growth rate of K. pnewoniae in soap solution was observed. The biodegradation rate of the recycling soap appeared to be slower as the thermal histories of the non-cooking oils became larger. This might be resulted from hydrolysis, in which the ester bonds in the oils are broken to produce hydroxyl group. It was also observed that the growth rate of the microorganism decreased with the increase in the thermal histories of the oils. As a result, it is desired that recycling soap should be produced from the non-cooking oils with the prober ranges of thermal histories to reduce water contamination. The non-cooking oils with larger thermal histories are considered to be recycling through the cracking process before used. Key Words : non-cooking oils, recycling soap, thermal history, biodegradation, microorganism growth.

• 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.

• KSBB Journal
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• 제13권5호
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• pp.606-614
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• 1998

In this study, biodegradation rate of Arabian light crude oil by mixed cultures of selected petroleum-degraders was determined. Their modes of hydrocarbon uptake were then observed to determine whether there are differences in biodegradation rate by the mixed cultures. By the mixed cultures of petroleum-degraders having same modes of hydrocarbon uptake, such as strain US1 and K1 (using pseudo-solubilized hydrocarbons by a biosurfactants), K2-2 and P1(using hydrocarbons by direct contact), CL 180 and IC-10 (mixed type of uptake modes), the biodegradation rates of aliphatics in the crude oil were increased more than those by their pure cultures, about 40%, 25% and 20%, respectively. Biodegradation rate of strain KH3-2 (using only water- dissolved hydrocarbons) was increased by mixed cultures with strain K1, CL180 or IC-10 possessing high emulsifying activity. However, the biodegradation rate of the crude oil was decreased about 20%-40% by the mixed cultures of petroleum-degraders having different mode of hydrocarbon uptake, such as addition of strain US1 or K1 in the cultures of K2-2 or P1. Biosurfactants produced by US1 or K1 seems to enhance the emulsification of crude oil in aqueous phase but inhibit the attachment of K2-2 or P1 to crude oil. As same phenomena, the addition to Triton X-100 into the culture of strain US1, K1, CL180, IC-10 or KH3-2 increased the biodegradation rate, but the addition in the culture of strain K2-2 or P1 decreased the biodegradation rate. The mixed culture made of CL180, IC-10 and KH3-2 degraded 61.5% of aliphatics and 69% of aromatics in 3% (v/v) of Arabian light crude oil added.

• Journal of Microbiology and Biotechnology
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• 제23권5호
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• pp.715-718
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• 2013

Density of catalytic organisms can determine the biodegradation capacity and specific biodegradation rate (SBR). A new index, biodegradation capacity utilization (BCU, %), was developed for estimating the extent of actual biodegradation of a gas compound over the full capacity. Three methanotrophic cultures were serially diluted (1-1/25), and methane SBR and BCU were measured. Consistently, biomass reduction increased the SBR and decreased the BCU. Linearity (p < 0.05, r > 0.97) between the BCU and cell density indicated the reflection of biodegradation capacity by BCU. Therefore, BCU is indicative of whether the density of catalytic organisms is pertinent for SBR evaluation of low-soluble gaseous compounds.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.462-466
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• 2003

This study was conducted to examine the potential of biosparging process in removing diesel contaminated soil and groundwater. The experiment was carried out lab-scale biosparging reactor and the biodegradation rate of diesel was evaluated as function of air injection rate and pattern. When renter was operated as air injection rate of 1000$m\ell$/min and pulsed air injection(15min pulse, 15min downtime), DO concentration in the renter was higher than another operating condition. The evidence for biodegradation of diesel was the $O_2$ utilization and $CO_2$ product following the cessation of sparging. Especially, air injection rate of 2000$m\ell$/min and pulsed air injection(15min pulse, 15min downtime) enhanced the diesel biodegradation during the operating. After 120day, the biodegradation rate of diesel was decreased as the lack of carbon source.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.174-177
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• 1998

The effects of surfactants affecting polycyclic Aromatic Hydrocarbon(PAHs) solubility and biodegradation in soil slurry were investigated. The critical micelle concentration(CMC) values of surfactants used in this study were 12.7mg/L(Brij 30), 13.4mg/L(Tween 80), 13.6mg/t(Triton X-100). The solubility of PAH increased as the Hydrophile-Lipophile Balance(HLB) value of surfactant decrease. At surfactant biodegradation and toxicity experiement using respirometer, Brij 30 did not show any toxic effect and substrate inhibition upon the level of 1.5g/L. Also, biodegradation of Brij 30 gave no reduction on the phenanthrene biodegradation rate. When the desorption rate of phenanthrene between sand and clay is compared, lower percentage of phenanthrene was desorbed at clay because of the larger surface aera and higher organic content of clay. At the biodegradation experiments of phenanthrene in soil slurry phase, more than 90% of initial phenanthrene adsorbed onto both sand and clay were biodegraded by phenanthrene- acclimated cultures.

• 미생물학회지
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• 제35권1호
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• pp.53-60
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• 1999

난분해성 다핵방향족 탄화수소인 pyrene의 생분해를 해수와 해사로 구성된 microcosm에서 조사하였다. 농도 100~1,000 ppm pyrene의 5주동안 자연분해도는 5~$20^{\circ}C$에서 1~11% 이고 이때 전환율은 310~2,200 ng/g(ml).day 이었다. 생분해에 미치는 분해균주 접종량, pyrene 농도, 온도와 계면활성제 첨가의 영향등을 영양염류가 투여된 시료에서 조사하였다. 혼합 분해균주접종시 해수보다는 해사에서 전환율이 전체적으로 높았으며 $10^{7}$cells/ml 접종시 pyrene 200 ppm 농도의 해사에서 대조구보다 분해도가 7.8배 높았다. 가장 높은 전환율 4,860 ng/g/day는 1,000 ppm pyrene이 첨가된 해사에 복합균주를 접종한 시료에서 측정되었다. Glucose 첨가시 해사에서는 배양초기에만 분해도의 증가가 나타났으며, 해수에서는 분해도가 8~10% 증가하였다. 계면활성제와 mineral oil 의 첨가는 오히려 pyrene 분해도를 대부분 감소시켰는데 CMC가 생분해에 큰 영향을 미치는 것으로 판단된다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.171-176
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• 2000

Bioremediation of hazardous hydrophobic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), is a major environmental concern due to their toxic and carcinogenic properties. Due to their hydrophobicity, the hydrophobic organic compounds are mainly associated with the soil organic matter or nonaqueous-phase liquids. A major question concerns the relationships between biodegradation and sorption. This work develops and utilizes a non- steady state model for evaluating the interactions between sorption and biodegradation of phenanthrene, a 3-ring PAH compound, in soil-slurry systems. The model includes sorption/desorption of a target compound, its utilization by microorganisms as a primary substrate existing in the dissolved phase and/or the sorbed phase in biomass and soil, oxygen transfer, and oxygen utilization as an electron acceptor. Biodegradation tests with phenanthrene were conducted in liquid and soil-slurry systems. The soil-slurry tests were performed with very different mass transfer rate: fast mass transfer in a flask test at 150 rpm, and slow mass transfer in a roller-bottle test at 2 rpm. In the slurry tests, phenanthrene was degraded more rapidly than in liquid tests, but with a similar rate in both slurry systems. Modeling analyses with several hypotheses indicate that a model without biodegradation of compound sorbed to the soil was not able to account for the rapid degradation of phenanthrene, particularly in the roller bottle slurry test. Reduced mass-transfer resistance to bacteria attached to the soil is the most likely phenomenon accounting for rapid sorbed-phase 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.