• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.89-91
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• 2000

Polynuclear aromatic hydrocarbon (PAH) compounds are highly carcinogenic chemicals and common groundwater contaminants that are observed to persist in soils. The adherence and slow release of PAHs in soil is an obstacle to remediation and complicates the assessment of cleanup standards and risks. Biological degradation of PAHs in soil has been an area of active research because biological treatment may be less costly than conventional pumping technologies or excavation and thermal treatment. Biological degradation also offers the advantage to transform PAHs into non-toxic products such as biomass and carbon dioxide. Ample evidence exists for aerobic biodegradation of PAHs and many bacteria capable of degrading PAHs have been isolated and characterized. However, the microbial degradation of PAHs in sediments is impaired due to the anaerobic conditions that result from the typically high oxygen demand of the organic material present in the soil, the low solubility of oxygen in water, and the slow mass transfer of oxygen from overlying water to the soil environment. For these reasons, anaerobic microbial degradation technologies could help alleviate sediment PAH contamination and offer significant advantages for cost-efficient in-situ treatment. But very little is known about the potential for anaerobic degradation of PAHs in field soils. The objectives of this research were to assess: (1) the potential for biodegradation of PAH in field aged soils under denitrification conditions, (2) to assess the potential for biodegradation of naphthalene in soil microcosms under denitrifying conditions, and (3) to assess for the existence of microorganisms in field sediments capable of degrading naphthalene via denitrification. Two kinds of soils were used in this research: Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS). Results presented in this seminar indicate possible degradation of PAHs in soil under denitrifying conditions. During the two months of anaerobic degradation, total PAH removal was modest probably due to both the low availability of the PAHs and competition with other more easily degradable sources of carbon in the sediments. For both Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS), PAH reduction was confined to 3- and 4-ring PAHs. Comparing PAH reductions during two months of aerobic and anaerobic biotreatment of MHS, it was found that extent of PAHreduction for anaerobic treatment was compatible with that for aerobic treatment. Interestingly, removal of PAHs from sediment particle classes (by size and density) followed similar trends for aerobic and anaerobic treatment of MHS. The majority of the PAHs removed during biotreatment came from the clay/silt fraction. In an earlier study it was shown that PAHs associated with the clay/silt fraction in MHS were more available than PAHs associated with coal-derived fraction. Therefore, although total PAH reductions were small, the removal of PAHs from the more easily available sediment fraction (clay/silt) may result in a significant environmental benefit owing to a reduction in total PAH bioavailability. By using naphthalene as a model PAH compound, biodegradation of naphthalene under denitrifying condition was assessed in microcosms containing MHS. Naphthalene spiked into MHS was degraded below detection limit within 20 days with the accompanying reduction of nitrate. With repeated addition of naphthalene and nitrate, naphthalene degradation under nitrate reducing conditions was stable over one month. Nitrite, one of the intermediates of denitrification was detected during the incubation. Also the denitrification activity of the enrichment culture from MHS slurries was verified by monitoring the production of nitrogen gas in solid fluorescence denitrification medium. Microorganisms capable of degrading naphthalene via denitrification were isolated from this enrichment culture.

• Journal of Microbiology and Biotechnology
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• 제26권11호
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• pp.1943-1950
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• 2016

Polycyclic aromatic hydrocarbons (PAHs) are commonly present xenobiotics in natural and contaminated soils. We studied three (phenanthrene, naphthalene, and biphenyl) xenobiotics, catabolism, and associated proteins in Sphingobium chungbukense DJ77 by two-dimensional gel electrophoresis (2-DE) analysis. Comparative analysis of the growth-dependent 2-DE results revealed that the intensity of 10 protein spots changed identically upon exposure to the three xenobiotics. Among the upregulated proteins, five protein spots, which were putative dehydrogenase, dioxygenase, and hydrolase and involved in the catabolic pathway of xenobiotic degradation, were induced. Identification of these major multifunctional proteins allowed us to map the multiple catabolic pathway for phenanthrene, naphthalene, and biphenyl degradation. A part of the initial diverse catabolism was converged into the catechol degradation branch. Detection of intermediates from 2,3-dihydroxy-biphenyl degradation to pyruvate and acetyl-CoA production by LC/MS analysis showed that ring-cleavage products of PAHs entered the tricarboxylic acid cycle, and were mineralized in S. chungbukense DJ77. These results suggest that S. chungbukense DJ77 completely degrades a broad range of PAHs via a multiple catabolic pathway.

• 공업화학
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• 제16권5호
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• pp.712-718
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• 2005

본 연구는 콜타르로 오염된 토양을 슬러리상 생물반응기로 처리할 때에 재순환수 첨가가 미치는 영향을 평가하고자 실시하였다. 실험실 규모의 슬러리상 생물반응기는 미생물활성이 최적으로 유지될 수 있도록 설정하였으며, 실험에 사용된 토양은 사질양토였다. 토양내의 콜타르와 14가지 PAHs 화합물의 농도는 가스크로마토그래피를 이용하여 분석하였다. 슬러리상 생물반응기는 2000 mg/kg 농도에서 재순환수 첨가의 영향이 미미하였다. 그러나 20000 mg/kg에서는 뚜렷한 효과를 나타내어 재순환수를 첨가한 경우의 1차반응속도상수와 제거율은 재순환수를 첨가하지 않은 경우 보다 각각 2.5배와 2.0배 정도가 증가되었다. 슬러리상 생물반응기에서 콜타르는 휘발(3.8~16.0%)과 분해(84.0~96.2%)에 의하여 제거되었으며, 분해에 의한 제거가 약 85% 이상이 되므로 주로 생물학적인 분해반응에 의하여 제거가 되는 것으로 평가되었다. 재순환수를 첨가한 경우에 고리수에 따른 PAHs 화합물의 제거에서 고리수가 3개인 경우에는 92.2~99.7%로 높은 제거율을 나타내었으며, 4개 이상의 고리수를 가진 화합물들은 분해되지 않거나 30% 미만으로 분해되었다.

• 한국환경보건학회지
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• 제31권5호
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• pp.423-430
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• 2005

This research was performed to evaluate the effectiveness of one- and dual-stage recycled-water systems in slurry bioreactor treatment for coal tar-contaminated soil. Silty loam soil was used for this research. Coal tar and 14 target PAHs (Polycyclic Aromatic Hydrocarbons) concentration in the soil were determined with gas chromatography. There was no significant difference between removal efficiencies of one- and dual-stage recycled water systems in case of about 4,000 mg coar tar/kg. However, the dual-stage system increased significantly the removal efficiency in case of about 20,000 mg coar tar/kg and the first-order kinetic constant of the system was over 1.5 times higher than that of one-stage recycled water system. 3-Ring compounds in PAHs was removed completely within 30 days of operation. Coar tar was removed in over 96% through biodegradation and removed in about 4% by evaporation. High correlation coefficient($r^2=0.91$) was found between water solubility and removal efficiency of the cyclic compounds.

• 유기물자원화
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• 제14권1호
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• pp.160-168
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• 2006

본 연구에서는 PAHs 오염토양의 펜톤처리시 식물성 식용유와 폐식용유의 첨가가 처리효율에 미치는 영향을 알아보고자 실시하였다. 토양 중 철성분 때문에 철용액을 첨가하지 않고 과산화수소만을 첨가한 경우에도 펜톤반응이 진행되었으며, 과산화수소는 3%에서 최대 효율을 나타내었다. 3%의 과산화수소만을 첨가한 경우에는 총 PAHs가 약 19% 제거되었는데 여기에 17.5 mM $FeSO_4$(III)를 첨가한 경우에는 25%가 제거되어 6% 정도의 효율증진을 나타내었다. 올리브유 1%를 펜톤반응과 동시 또는 전에 첨가한 경우 제거효율은 37~38%로써 펜톤처리만을 한 경우의 22.3% 보다 약 15%정도 제거효율을 증가시킬 수 있었다. 올리브유, 콩식용유, 그리고 폐식용유 농도를 1%와 5%로 하여 주입한 결과 대부분 35% 이상의 처리효율을 나타내었으며, 오일의 종류와 농도에 따른 영향은 크지 않았다. 폐식용유를 사용하였을 때 고가의 올리브유를 사용한 경우와 큰 효율차이를 나타내지 않았으므로 폐식용유 사용시 추가비용이 거의 소요되지 않는 장점이 있을 것으로 판단된다. 3% 과산화수소와 2.5 mM $FeSO_4$에서 1% 올리브유 첨가 후 15분이 지나서 펜톤반응을 실시한 경우 벤젠고리 3~4개와 5~6개인 화합물의 제거율은 펜톤반응만을 실시한 경우 보다 각각 13%와 17% 정도 증가하였다.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2001년도 추계학술대회
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• pp.157-163
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• 2001

Mycolic acid-containing gram-positive bacteria, so called nocardioform actinomycetes, have become a great interest to environmental microbiologists due to their metabolic versatility, multidegradative capacity and potential for bioremediation of priority pollutants. For example, Rhodococcus rhodochrous N75 was able to metabolize 4-methy1catechol via a modified $\beta$-ketoadipate pathway whereby 4-methylmuconolactone methyl isomerase catalyzes the conversion of 4-methylmuconolactone to 3-methylmuconolactone in order to circumvent the accumulation of the 'dead-end' metabolite, 4-methylmuconolactone. R. rhodochrous N75 has also shown the ability to transform a range of alkyl-substituted catechols to the corresponding muconolactones. A novel 3-methylmuconolactone-CoAsynthetase was found to be involved in the degradation of 3-methylmuconolactone, which is not mediated in a manner analogous to the classical $\beta$-ketoadipate pathway but activated by the addition of CoA prior to hydrolysis of lactone ring, suggesting that the degradative pathway for methylaromatic compounds by gram-positive bacteria diverges from that of proteobacteria. Mycobacterium sp. Strain PYR-l isolated from oil-contaminated soil was capable of mineralizing various polyaromatic hydrocarbons (PAHs), such as naphthalene, phenanthrene, pyrene, fluoranthrene, 1-nitropyrene, and 6-nitrochrysene. The pathways for degradation of PAHs by this organism have been elucidated through the isolation and characterization of chemical intermediates. 2-D gel electrophoresis of PAH-induced proteins enabled the cloning of the dioxygenase system containing a dehydrogenase, the dioxygenase small ($\beta$)-subunit, and the dioxygenase large ($\alpha$)-subunit. Phylogenetic analysis showed that the large a subunit did not cluster with most of the known sequences except for three newly described a subunits of dioxygenases from Rhodococcus spp. and Nocardioides spp. 2-D gel analysis also showed that catalase-peroxidase, which was induced with pyrene, plays a role in the PAH metabolism. The survival and performance of these bacteria raised the possibility that they can be excellent candidates for bioremediation purposes.

• 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.

• 한국산학기술학회논문지
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• 제3권4호
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• pp.295-302
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• 2002

본 연구는 천연계 계면활성제의 하나인 사이클로덱스트린을 이용한 화학적 토양세정을 다룬다. 두가지 polycyclic aromatic hydrocarbon인 phenanthrene과 naphthalene을 오염물질로 선정하고 토양종류 및 세정강도를 주변수로 하여 수직칼럼 상에서의 오염물질 제거효과를 분석, 고찰하였다. 실험실 규모의 연구결과, 오염원 제거효율은 세정액의 유량, 농도, 온도 및 토양칼럼의 공극률에 비례하는 것으로 나타났으며, 형광광도 분석과 methylene blue와 같은 염료 라벨링 분석을 통하여 초기 세정은 토양과 계면활성제의 흡착에 의존하고 세정이 거듭될수록 유체흐름에 의한 전단력이 주요변수임을 확인할 수 있었다. 본 데이터는 향후 pilot 규모의 현장세정시 기초자료로 활용가능하며, 세정전략 (회분식, 연속식)수립에 유용할 것으로 사료된다.

• 대한환경공학회지
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• 제34권7호
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• pp.445-453
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• 2012

본 연구에서는 PAHs 오염토양의 자연 풍화 및 화학적 생물학적 처리과정에서 반응부산물로 흔히 발견되는 PAH-케톤화합물인 1-indanon (1-ID)을 대상으로 페놀계 반응매개체 존재 하에서의 망간산화물에 의한 산화 변환 제거특성 및 용존 자연유기물인 휴믹산(HA)의 존재에 따른 영향을 조사하였다. 반응성 평가 실험은 수용액 상에서 회분식(10 mg/L 1-ID, 0.3 mM phenolic mediators, $1.0g/L\;{\delta}-MnO_2$, at pH 5)으로 수행 하였으며, 페놀계의 반응매개체(phenolic mediator)는 자연산 페놀화합물로서 휴믹물질의 모델 화합물로서도 널리 사용되고 있는 11종을 사용하였다. 실험결과 1-ID은 망간산화물 자체에 대하여는 비반응성을 띠었으나 페놀계 반응매개체 존재 하에서 교차-결합(cross-coupling)반응을 통해 제거됨을 HPLC 분석을 통해 확인하였으며, 1-ID의 제거율은 반응 2일 경과 후 9.2~71.2%범위에서 페놀계 반응매개체의 구조적 특성에 따라 다르게 나타났다. 각 반응매개체 존재 하에서의 1-ID의 교차결합 반응은 유사1차 반응 속도식을 따랐으며, 초기 반응속도 상수 값($K_{int}$, $hr^{-1}$)은 0.48~15.0의 넓은 범위에서 나타났다. 1-ID의 제거효율(제거율, 속도상수)은 -OH, $-OCH_3$ 등 전자주게(electron donating) 작용기를 포함하는 반응매개체에서 높았으며, -COOH, -CHO 등 전자받게(electron withdrowing) 작용기를 포함하는 반응매개체일수록 낮았다. 또한 동일 반응 조건에서 HA 존재에 따른 영향을 검토한 결과 낮은 HA 농도(< 2 mg/L) 조건에서는 1-ID 제거효율의 상승효과를 보였으나 전체적으로는 HA 주입 농도가 증가할수록 교차 결합 반응효율이 저하됨을 확인하였다.