• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1999년도 추계학술발표회
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• pp.19-22
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• 1999

A microbial consortium derived from a gasoline-contaminated sites was enriched on toluene in 100-mL serum bottle and was found to degrade benzene(B), toluene(T), ethylbenzene(EB), and xylenes(X). Studies conducted to determine the temperature effects and BTEX concentration on BTEX degradation. The results indicated that lowering temperature significantly decreased BTEX degradation rates and varing the BTEX concentration also changed substrate degradation patterns.

• Korean Chemical Engineering Research
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• 제52권5호
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• pp.638-646
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• 2014

본 연구에서는 modified Fenton 공정에서 Fe(II)과 Fe(III)에 대한 유 무기 착제의 효율성 평가를 위해 BTEX(benzene, toluene, ethylbenzene, xylene) 분해효율을 관찰하였다. 적용된 유 무기착제의 종류는 구연산과 피로인산을 선정하였다. Fe(III)과 구연산이 적용되어진 modified Fenton 공정에서, 구연산의 농도가 증가할수록 BTEX의 분해율이 감소하였지만, 피로인산의 경우에는 농도가 증가할수록 BTEX의 분해율이 증가하였다. 또한 Fe(III)이 적용되어진 modified Fenton 공정에서 무기착제인 피로인산이 적용되어진 경우, 유기착제인 구연산이 적용되어진 경우보다 상대적으로 높은 BTEX의 분해율을 나타내었다. Fe(II)에 유 무기 착제가 적용되어진 modified Fenton 공정을 비교한 결과, Fe(II)과 구연산의 몰비가 1:1일 때 pH 변화를 최소화시킴과 동시에 BTEX의 높은 분해율을 보였다. 결과적으로 과산화수소의 효율성, 철 침전물 생성여부, 오염물질 분해율 등이 고려되어질 때, 100 ppm의 벤젠분해를 위한 최적 Fe(II), 구연산 그리고 과산화수소의 농도 조건은 7 mM/7 mM/500 mM였다.

• 대한환경공학회지
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• 제22권2호
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• pp.375-383
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• 2000

유일로 오염된 지역의 토양에서 toluene을 탄소원으로 이용하는 혼합미생물을 분리하여 toluene, benzene, ethylbenzene 및 xylene isomers(BTEX)의 분해특성을 관찰하였다. 단일기질 실험에서는 모든 BTEX의 분해가 이루어졌으며 toluene, benzene, ethylbenzene, p-xylene 순서로 분해되었다. BTEX 혼합기질 분해실험에서는 단일기질일 때보다 분해속도가 상대적으로 느려졌으며, ethylbenzene이 benzene보다 먼저 분해되는 것이 관찰되었다. 이중 혼합물질 반응 실험에서는 방해작용(inhibition), 촉진작용(stimulation), 그리고 비반응(non-interaction)과 같은 다양한 기질반응이 관찰되었으며, ethylbenzene은 benzene, toluene, xylene의 분해에 강한 방해영향을 주었다. Xylene 분해특성에서 m- 및 p-xylene은 혼합미생물에 탄소원으로 이용되었으며 benzene이나 toluene이 동시에 존재할 때는 xylene isomer의 분해가 촉진되었다. 그러나 o-xylene의 분해는 benzene에 의해서만 촉진되었다.

• Journal of Microbiology and Biotechnology
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• 제33권7호
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• pp.875-885
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• 2023

Volatile organic compounds such as benzene, toluene, ethylbenzene, and isomers of xylenes (BTEX) constitute a group of monoaromatic compounds that are found in petroleum and have been classified as priority pollutants. In this study, based on its newly sequenced genome, we reclassified the previously identified BTEX-degrading thermotolerant strain Ralstonia sp. PHS1 as Cupriavidus cauae PHS1. Also presented are the complete genome sequence of C. cauae PHS1, its annotation, species delineation, and a comparative analysis of the BTEX-degrading gene cluster. Moreover, we cloned and characterized the BTEX-degrading pathway genes in C. cauae PHS1, the BTEX-degrading gene cluster of which consists of two monooxygenases and meta-cleavage genes. A genome-wide investigation of the PHS1 coding sequence and the experimentally confirmed regioselectivity of the toluene monooxygenases and catechol 2,3-dioxygenase allowed us to reconstruct the BTEX degradation pathway. The degradation of BTEX begins with aromatic ring hydroxylation, followed by ring cleavage, and eventually enters the core carbon metabolism. The information provided here on the genome and BTEX-degrading pathway of the thermotolerant strain C. cauae PHS1 could be useful in constructing an efficient production host.

• 한국물환경학회지
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• 제21권4호
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• pp.347-352
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• 2005

The isolated microorganisms, Pseudomonas stutzeri, Raoultella planticola (Klebsiella), Serratia fonticola from petroleum contaminated soil were enriched on benzene, toluene, ethylbenzene, o-xylene as carbon and energy sources, respectively. And the degradation characteristics of BTEX was observed in the mixed BTEX substrates. We found that the BTEX in mixed substrates were degraded more than 50% by three isolated microorganisms. Among three isolated microorganisms, the highest degradation rate was observed in Pseudomonas stutzeri, but the degradation rate was different according to microorganisms. In order to increase the degradation efficiency, we applied the co-culture of isolated three microorganisms. The mixture rate of pseudomonas stutzeri : Raoultella planticola (Klebsiella) : Serratia fonticola was follows ; 1:2:1, 1:1:2, and 2:1:1, respectively. In two co-culture of 1:2:1 and 1:1:2, degradation rate was lower than isolated microorganisms. However, degradation rate became higher than isolated microorganisms and the degradation rate of benzene, toluene, and ethylene was more than 95% in co-culture of 2:1:1. The degradation rate increased through the co-culture of isolated microorganisms, however, the growth rate decreased. This was resulted from the substrate competition between microorganisms. The co-culture of microorganisms is a effective method to increase the degradation efficiency of BTEX and the co-culture mixing rate is a important factor for determination of degradation efficiency.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.179-182
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• 2000

Toluene-degrading bacterium, Microbacterium esteraromaticum CS3-1 was isolated from the biofilter for the removal of BTEX. Microbacterium esteraromaticum CS3-1 was shown to utilize toluene as a primary carbon and energy source. Effect of mixed BTEX gases on toluene degradation rate by M. esteraromaticum CS3-1 was investigated in this study. Toluene degradation rate was 2.26(only toluene), 2.06(toluene+benzene), 2.57(toluene+ethylbenzene), and 4.74(toluene+xylene) mmole $toluene\;{\cdot}\;g-DCW^{-1}\;{\cdot}\;h^{-1}$. Toluene degradation rate was 2.26(only toluene), 1.23(toluene+benzene+ethylbenzene), 1.52 (toluene+ethylbenzene+xylene), and 1.76(toluene+benzene+ethylbenzene+xylene) mmole $toluene\;{\cdot}\;g-DCW^{-1}\;{\cdot}\;h^{-1}$. The presence of BTEX compounds over three mixtures had a negative effect on toluene degradation rate. Toluene degradation rates were enhanced by the presence of ethylbenzene or xylene, whereas the presence of benzene had a negative effect on toluene degradation rate in comparison with toluene degradation rate when only toluene is existent.

• 한국지반환경공학회 논문집
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• 제15권5호
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• pp.39-46
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• 2014

본 연구에서는 다양한 호기/혐기조건에서 유류오염물질인 및 MTBE의 생분해 특성을 비교하고, 특히 탈질 조건에서 질산염 영향을 조사하여 유류오염지역의 혐기적 자연정화방법의 적용 가능성을 평가하고자 한다. 단일기질 및 혼합기질 분해실험 결과, BTEX는 3가지 실험조건에서 차이는 있었으나 모두 분해가 일어났다. 그러나 benzene과 p-xylene은 호기성 조건에서 초기 공급된 용존 산소의 부족으로 인하여 분해가 지연되는 것으로 나타났다. 또한 혼합기질에서는 단일기질에 비해 BTEX 분해가 기질 경쟁관계로 인해 다소 지연되는 경향이 관찰되었다. MTBE는 탈질 조건에서만 생분해가 관찰되었으나, TBA 축적 없이 $CO_2$로 무기화되는 것으로 추정된다. 또한 BTEX 및 MTBE 분해에 대한 질산염 농도의 영향 실험 결과, 저농도(>50 mg/L)에서 BTEX 분해는 제한되었으며, 고농도 질산염(<200 mg/L) 조건하에서는 BTEX 분해가 억제되는 현상이 관찰되었다. 본 연구에서 도출된 결과는 유류오염지역의 경우 호기/혐기성 조건에서 자연 생분해를 유도할 수 있을 것으로 예상된다.

• KSBB Journal
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• 제13권5호
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• pp.561-568
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• 1998

Two cometabolic trichloroethylene (TC) degraders, Pseudomonas putida F1 and Burkholderia (Pseudomonas) cepacia G4, were found to catabolize phenol, benzene, toluene, and ethylbenzene as carbon and energy sources. Resting cells of P. putida F1 and B. cepacia G4 grown in the presence of toluene and phenol, respectively, were able to degrade not only benzene, toluene and ethylenzene but also TCE and p-xylene. However, these two strains grown in the absence of toluene or phenol did not degrade TCE and p-xylene. Therefore, it was tentatively concluded that cometabolic degradation of TC and p-xylene was mediated by toluene dioxygenase (P. putida F1) or toluene-2-monooxygenase (B. cepacia G4). Maximal degradation rates of BTEX and TCE by toluene- and phenol-induced resting cells of P. putida F1 and B. cepacia G4 were appeared to be 4-530 nmol/(min$.$mg cell protein) when a single compound was solely served as a target substrate. In case of double substrates, the benzene degradation rate by P. putida F1 in the presence of toluene was decreased up to one seventh of that for the single substrate. TCE degradation rate was also linearly decreased as toluene concentration increased. On the other hand, toluene degradation rate was enhanced by benzene and TCE. For B. cepacia G4, degradation rates of TCE and toluene increased 4 times in the presence of 50 ${\mu}$M phenol. From these results, it was concluded that a degradation rate of a compound in the presence of another cosubstrate(s) could not be predicted by simply generalizing antagonistic or synergistic interactions between substrates.

• 한국물환경학회지
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• 제21권4호
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• pp.403-409
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• 2005

Methyl tert-butyl ether (MTBE) contamination in groundwater often coexists with benzene, toluene, ethylbenzene, and xylene (BTEX) near the source of the plume. Then, groundwater contamination problems have been developed in areas where the chemical is used. Common sources of water contamination by BTEX and MTBE include leaking underground gasoline storage tanks and leaks and spills from above ground fuel storage tanks, etc. In oil-contaminated environments, anaerobic biodegradation of BTEX and MTBE depended on the concentration and distribution of terminal electron acceptor. In this study, effect of electron acceptor on the anaerobic biodegradation for BTEX and MTBE-contaminated soil was investigated. This study showed the anaerobic biodegradation of BTEX and MTBE in two different soils by using nitrate reduction, ferric iron reduction and sulfate reduction. The soil samples from the two fields were enriched for 65 days by providing BTEX and MTBE as a sole carbon source and nitrate, sulfate or iron as a terminal electron acceptor. This study clearly shows that degradation rate of BTEX and MTBE with electron acceptors is higher than that without electron acceptors. Degradation rate of Ethylbenzene and Xylene is higher than that of Benxene, Toluene, and MTBE. In case of Benzene, Ethylbenzene, and MTBE, nitrate has more activation. In case of Toluene and Xylene, sulfate has more activation.

• Journal of Microbiology and Biotechnology
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• 제12권6호
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• pp.909-915
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• 2002

The biodegradation of BTEX components (benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene) individually and in mixtures was investigated using the o-xylene-degrading thermo-tolerant bacterium Ralsronia sp. strain PHS1 , which utilizes benzene, toluene, ethylbenzene, or o-xylene as its sole carbon source. The results showed that as a single substrate for growth, benzene was superior to both toluene and ethylbenzene. While growth inhibition was severe at higher o-xylene concentrations, no inhibition was observed (up to 100 mg $l^-1$) with ethylbenzene. In mixtures of BTEX compounds, the PHS1 culture was shown to degrade all six BTEX components and the degradation rates were in the order of benzene, toluene, o-xylene, ethylbenzene, and m- and p-xylene. m-Xylene and p-xylene were found to be co-metabolized by this microorganism in the presence of the growth-supporting BTEX compounds. In binary mixtures containing the growth substrates (benzene, toluene, ethylbenzene. and o-xylene), PHS1 degraded each BTEX compound faster when it was alone than when it was a component of a BTEX mixture, although the degree of inhibition varied according to the substrates in the mixtures. p-Xylene was shown to be the most potent inhibitor of BTEX biodegradation in binary mixtures. On the other hand, the degradation rates of the non-growth substrates (m-xylene and p-xylene) were significantly enhanced by the addition of growth substrates. The substrate utilization patterns between PHS1 and other microorganisms were also examined.