• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.337-345
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• 2005

The degradation of phenanthrene, a model PAH compound, by microorganisms either in the mixed culture or individual strain, isolated from oil-contaminated soil in oil refmery vicinity sites, was examined. The effects of pH, temperature, initial concentration of phenanthrene, and the addition of carbon sources on biodegradation potential were also investigated. Results showed that soil samples collected from four oil refinery sites in Korea had different degrees of PAH contamination and different indigenous phenanthrene-degrading microorganisms. The optimal conditions for phenanthrene biodegradation were determined to be 30$^{circ}C$ and pH 7.0. A significantly positive relationship was observed between the microbial growth and the rate of phenanthrene degradation. However, the phenanthrene biodegradation capability of the mixed culture was not related to the degree of PAH contamination in soil. In low phenanthrene concentration, the growth and biodegradation rates of the mixed cultures did not increase over those of the individual strain, especially IC10. High concentration of phenanthrene inhibited the growth of microbial strains and biodegradation of phenanthrene, but was less inhibitory on the mixed culture. Finally, when non-ionic surfactants such as Brij 30 and Brij 35 were present at the level above critical micelle concentrations (CMCs), phenanthrene degradation was completely inhibited and delayed by the addition of Triton X100 and Triton N101.

• 한국환경과학회지
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• 제2권2호
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• pp.95-102
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• 1993

In order to find the most fitted biodegradation model, biodegradation models to the initial 4-chlorophenol concentrations were investigated and had been fitted by the linear regression. The degrading bacterium, EL-091S, was selected among phenol-degraders. The strain was identified with Pseudomows sp. from the result of taxonomical studies. The optimal condition for the biodegradation was as fellows: secondary carbon source, concentration of ammonium nitrate, temperature and pH were 200mg/l fructose, 600 mg/l, $30^{\circ}C$ and 7.0 respectively. The highest degradation rate of the 4-chlorophenol was about 58% for 24 hours incubation on the optimal condition. Biodegradation kinetics model of 5 mg/l 4-Chlorophenol, 10 mg/l 4-chlorophenol and 50 mg/l 4-chlorophenol were fitted the zero order kinetics model, respectively. Key Words : 4-chlorophenol, Pseudomonas sp., zero order kinetics model.

• 한국균학회지
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• 제23권4호통권75호
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• pp.348-353
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• 1995

Poly (3-hydroxybutyrate)(PHB) 의 Penicillium pinophilum에 의한 생분해성을 변형 Sturm Test 법으로 조사하였다. 활성오니를 사용한 경우보다 PHB의 생분해성이 비교적 재현성있게 측정되었으며 PHB의 생분해를 가장 빠르게 진행시키는 최적 포자 접균량은 1 %(v/v)이었다. 생분해 속도는 시료의 표면적에 따라 증가하였으나 비례적으로 상승하지 않아 분해가 시료의 표면 뿐만 아니라 내부에서도 진행됨을 나타내었다. 반응 배지내의 질소원 함량에 따라 PHB의 생분해 속도는 증가하다가 점근값을 보여 질소원이 depolymerase 효소의 합성에 필요한 원소임을 보였다.

• 대한환경공학회지
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• 제37권7호
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• pp.404-411
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• 2015

생물활성탄(BAC) 공정에서의 공탑 체류시간(EBCT) 및 수온의 변화에 따른 9종의 halonitromethanes (HNMs)류들의 생물분해 특성을 평가하였다. 수온 $10^{\circ}C$와 $25^{\circ}C$에서 EBCT를 5분~15분까지 변화시켜 실험하였다. 생물활성탄 공정에서 HNMs류 9종의 생물분해율은 EBCT와 수온에 따라 큰 영향을 받았으며 EBCT와 수온이 증가할수록 생물분해율이 증가하였으며, HNMs류들의 종류에 따른 생물활성탄 공정에서의 생물분해율은 DBCNM과 TBNM이 가장 높았고, CNM과 DCNM이 가장 낮았다. DBCNM과 TBNM을 제외한 HNMs류 7종에 대해 BAC 공정에서의 생물분해 속도상수($k_{bio}$)는 수온이 $10^{\circ}C$에서 $25^{\circ}C$로 상승하였을 경우, $0.0797{\sim}0.7657min^{-1}$에서 $0.1245{\sim}1.8421min^{-1}$로 증가하여 1.6~2.4배 정도 증가하였다.

• 한국미생물·생명공학회지
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• 제37권3호
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• pp.243-247
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• 2009

The usage of ethanol (EtOH)-blended gasoline (gasohol), has been increasing in recent years. EtOH has influence on the distribution and biodegradation of aromatic compounds such as BTEX (benzene (B), toluene (T), ethylbenzene (B), and xylene (X)) that are gasoline compositions. In this study, the effect of EtOH on the aerobic biodegradation of B, T and E was investigated using a BTEX and EtOH-degrading bacterium, Rhodococcus sp. EH831. The degradation rates of B in the conditions of 1:1, 1:4, and 1:0.25 mixtures with EtOH (B:EtOH, mol:mol) were ranged from $3.82{\pm}0.20$ to $5.00{\pm}0.37{\mu}mol{\cdot}g-dry$ cell wight $(DCW)^{-1}{\cdot}h^{-1}$. The degradation rate of T was the fastest in the 1:0.25 mixture ($6.63{\pm}0.06{\mu}mol{\cdot}g-DCW^{-1}{\cdot}h^{-1}$), and it was the lowest in the 1:4 mixture ($4.41{\pm}0.04{\mu}mol{\cdot}DCW^{-1}{\cdot}h^{-1}$). The degradation rates of E were increased with increasing the addition amount of EtOH: The degradation rate of E was the highest in the 1:4 mixture ($1.60{\pm}0.03{\mu}mol{\cdot}g-DCW^{-1}{\cdot}h^{-1}$), and the rates were $1.42{\pm}0.06$, $1.30{\pm}0.01$, and $1.01{\pm}0.30{\mu}mol{\cdot}g-DCW^{-1}{\cdot}h^{-1}$ in the 1:1, 1:0.25, 1.0 mixtures, respectively. In conclusion, the biodegradation of B, T, E by Rhodococcus sp. EH831 was not significantly inhibited by the co-existence of EtOH.

• 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 the Korean Wood Science and Technology
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• 제26권3호
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• pp.53-62
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• 1998

In this research, 7 species of white rot fungi were used for determining the resistance against pentachlorophenol (PCP). Three fungi with good PCP resistance were selected for evaluating the biodegradability, and biodegradation mechanism by HPLC and GC/MS spectrometry. Among 7 fungi, there were significant differences on PCP resistance on 4 different PCP concentrations. In the concentrations of 50 and 100ppm ($\mu$g of PCP per g of 2% malt extract agar), most fungi were easily able to grow, and well suited to newly PCP-added condition, but in that of more than 250ppm, the mycelia growths of Ganoderma lucidum 20435, G. lucidum 20432, Pleurotus ostreatus, and Daldinia concentrica were significantly inhibited or even stopped by the addition of PCP to the culture. However, Trametes versicolor, Phanerochaete chrysosporium, and Inonotus cuticularis still kept growing at 250ppm, indicating the potential utilization of wood rot fungi to high concentrated PCP biodegradation. Particularly, P. chrysosporium even showed very rapid growth rate at more than 500ppm of PCP concentration. Three selected fungi based on the above results showed an excellent biodegradability against PCP. P. chrysosporium degraded PCP up to 84% on the first day of incubation, and during 7 days, most of added PCP were degraded. T. versicolor also showed more than 90% of biodegradability at 7th day, and even though the initial stage of degradation was very slow, I. cuticularis has been approached to 90% at 21 st day after incubation with dense growing pattern of mycelia. Therefore, the PCP biodegradability was definitely dependent on the rapid suitability of fungi to newly PCP-added condition. In addition, the PCP biodegradation by filtrates of P. chrysosporium, T. versicolor, and I. cuticularis was very minimal or limited, suggesting that the extracellular enzyme system may be not so significantly related to the PCP biodegradation. Among the biodegradation metabolites of PCP, the most abundant one was pentachloroanisole which resulted in a little weaker toxicity than PCP, and others were tetrachlorophenol, tetrachloro-hydroquinone, benzoic acid, and salicylic acid, suggesting that PCP may be biodegraded by several sequential reactions such as methylation, radical-induced oxidation, dechlorination, and hydroxylation.

• KSBB Journal
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• 제15권3호
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• pp.247-253
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• 2000

This study was aimed to enhance polycyclic aromatic hydrocarbon(PAHS) biodegradation rate by repeated-batch treatment using immobilized cells of Phanerochaete chrysosporium. In the repeated-batch operations with 30 mg/L of pyrene the maximum degradation rate was 6.58 mg/L day. As the number of batches increased the concentration of immobilized cells significantly decreased and the degradation rate and specific acitivity gradually increased to a maximum value and then decreased. To have PAH degradation activity and cell mass recovered one batch of cultivation using the growth medium instead of the PAH-degrading medium was carried in the course of repeated-batch operations. This maximum degradation rates of pyrene and anthracene were 4.29 and 4.46 mg/L$.$day respectively. Overall the rate of PAH degradation could be enhanced 2.5-30 folds by using immobilized cells compared to the case of using suspended cells.

• 대한환경공학회지
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• 제39권3호
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• pp.124-131
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• 2017

생물활성탄 공정과 안트라사이트를 여재로 사용한 biofilter에서 공탑 체류시간(EBCT)과 수온의 변화에 따른 8종의 고지혈증 치료제류(blood lipid regulator agents, BLLAs)의 생물분해 특성을 평가하였다. 수온 $8^{\circ}C$, $16^{\circ}C$ 및 $24^{\circ}C$에서 공탑 체류시간을 5분~15분까지 변화시켰다. 생물활성탄 공정에서 고지혈증 치료제류 8종의 생물분해 제거율은 공탑 체류시간과 수온의 변화에 많은 영향을 받았으며, 공탑 체류시간과 수온이 증가할수록 생분해 제거율이 증가하였다. 고지혈증 치료제류의 종류에 따른 생물활성탄 공정에서 생분해 제거율은 statin계의 경우 simvastatin이 가장 높았으며 다음으로 mevastatin, fluvastatin 및 atorvastatin 순이었다. 또한, Fibrate계 고지혈증 치료제들의 생물분해능은 fenofibrate가 가장 높았으며 다음으로 gemfibrozil, bezafibrate, clofibric acid순이었다. BAC 공정에서 생물분해 제거능이 가장 낮은 clofibric acid와 atorvastatin의 생물분해 속도상수($k_{bio}$)는 수온이 $8^{\circ}C$에서 $24^{\circ}C$로 상승하였을 경우, 각각 $0.0075min^{-1}$과 $0.0122min^{-1}$에서 $0.0540min^{-1}$과 $0.0866min^{-1}$으로 증가하여 각각 7.2배 및 7.1배 정도 증가하였다.

• Journal of Biosystems Engineering
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• 제24권4호
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• pp.359-364
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• 1999

A theoretical model was developed to evaluate the influence of control variables on the composting performance in a bin composting system. The model was verified using pilot scale composting system. Simulation of the composting temperature according to air flow rate and composting bin size was conducted using the mathematical model. High composting temperature above 55$^{\circ}C$ needed to kill a pathogen was maintained for longer periods as the air flow rate was lower and the bin size was larger. Optimum air flow rate was 0.77L/min/kg.DM for the experimental pilot scale bin system. The size of composting bin should be large enough to maintain the higher composting temperature for required periods.