• Korean Journal of Microbiology
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• v.44 no.2
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• pp.156-163
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• 2008

In this study, we isolated 32 strains of kerosene degrading bacteria from oil contaminated soil by enrichment culture. Isolates were screened for kerosene degradation efficiencies and K14 were selected which had the highest removal efficiency for 1,000 mg/L of kerosene. K14 were identified as Pseudomonas aeruginosa by morphological, biochemical test and 16S rDNA analysis. The optimal culture condition were determined as initial inoculated cell concentration, 1.0 g/L; substrate concentration, 1,000 mg/L; temperature $30^{\circ}C$; pH 7. When we enforced batch test in this condition, K14 degraded 72% of kerosene with 1,000 mg/L during 72 hr. And, at low concentration (200 mg/L), K14 degraded 95.8% of kerosene during 48 hr. As a result, kerosene biodegradation by Pseudomonas aeruginosa K14 could be useful for clean up of groundwater and soil contaminated with crude oil.

• Korean Journal of Microbiology
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• v.44 no.1
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• pp.37-42
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• 2008

Optimal conditions for the biodegradation of endocrine-disrupting bisphenol A (BPA) were examined for the white rot fungus Trametes versicolor isolated in Korea. T. versicolor degraded 100% of 50 mg/L bisphenol A during 12 hr in yeast extract-malt extract-glucose (YMG) medium. When BPA was added to the 5-day preincubated fungal culture in YMG medium, all BPA was removed in 2 hr. T. versicolor could efficiently degrade BPA at $35^{\circ}C$, pH 6 in YMG medium. T. versicolor could more easily remove BPA of $1{\sim}25\;mg/L$ than that of higher concentrations ($50{\sim}100\;mg/L$) in YMG medium. T. versicolor degraded 100% of 50 mg/L BPA for 36 h in a minimal medium, which is lower degradation rate than that in YMG medium. Optimal conditions for BPA biodegradation in the minimal medium were similar to those in YMG medium. When BPA (50 mg/L) was added into domestic wastewater, it could be completely removed by T. versicolor. During the biodegradation of BPA by T. versicolor in YMG medium, its estrogenic activity decreased.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.3
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• pp.110-116
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• 2006

In this study, the biodegradation rate of paraoxon, that is an organophosphate pesticide, was enhanced by recombinant Escherichia coli harboring organophosphorus hydrolase (OPH). The optimum conditions were 8.5 of initial pH and 5.0% of acetone for the enhancement of specific whole cell OPH activity. When the OPH was produced to 498 Unit/L, 98% of 275mg/L paraoxon was degraded within 10 minutes, and thus the biodegradation rate was enhanced to $29.2mg/g{\cdot}min$. The results implied that practical bioremediation technology developed in this study was an effective method to degrade residual organophosphate pesticide in ground water or soils in a short time.

• Journal of Microbiology and Biotechnology
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• v.5 no.1
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• pp.41-47
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• 1995

Biodegradation of toluene in liquid effluent stream was carried out using biofilms of Pseudomonas putida formed on celite particles in the bubble column bioreactor. Silicon rubber tubing was installed at the bottom of the bioreactor and liquid toluene was circulated within the tubing. Toluene diffused out of the tube wall and was transferred into the culture broth where degradation by biofilms occurred. The operating variables affecting the formation of biofihns on celite particles were investigated in the bubble column bioreactor, and it was found that formation of bifilm is favored by high dilution rate and supply rate of carbon source which stimulate the growth of initially attached cells. Continuous biodegradation of toluene using biofilms was stablely conducted in the bioreactor for more than one month without any significant fluctuation, showing a removal efficiency higher than 95% at the toluene transfer rate of 1.2 g/L/h.

• Clean Technology
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• v.8 no.4
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• pp.199-203
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• 2002

To investigate the optimal conditions for biodegradation of toluene by Pseudomonas fluorescens KCTC 1767 in a batch soil-bioreactor, the effects of rpm change from 60 to 180, and temperature change from $15^{\circ}C$ to $30^{\circ}C$ in a batch culture and the flow rate change from 55 mL/min to 85 mL/Min in soil-bioreactor on the biodegradation of toluene were studied. In a batch culture the optimal operating conditons were 60 rpm, and $30^{\circ}C$ at initial pH 7, In a soil-bioreactor the optimal flow rate was 55 mL/min in the flow rate of circulation. The lower flow rate of circulation may help to biodegrade toluene adsorped in soil and dissolved in underground water.

• Journal of Korean Society on Water Environment
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• v.20 no.3
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• pp.256-264
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• 2004

Adsorption characteristics of three endocrine disruptors, amitrol, nonylphenol, and bisphenol-A, were evaluated depending on the type and service duration of activated carbon (AC). Bituminous coal-, wood-, and coconut-based coals were tested. Bituminous coal-based AC (BCAC) had the greatest sorption capacity for the three chemicals tested, followed by wood-based AC (WAC) for nonylphenol and coconut palm-based AC (CAC) for bisphenol-A. During the column test, amitrol removal efficiency increased over time, indicating that hydrophilic endocrine disruptors are biodegraded in the AC column. Removal efficiencies of hydrophobic compounds such as nonylphenol and bisphenol-A decreased over time since the main removal mechanism was adsorption. The order of the amitrol removal was: BCAC-5.9 yr, CAC-3.l yr > BCAC-2.2 yr > BCAC-virgin > CAC-virgin > WAC-virgin > WAC-3.l yr. In general, used AC had greater removals than virgin AC. The order of the bisphenol-A removal was: CAC-virgin > BCAC-2.2 yr > CAC-3.l yr > WAC-virgin > BCAC-5.9 yr > WAC-3.l yr. The order of the nonylphenol removal was: BCAC-virgin > WAC-virgin > CAC-3.1 yr, WAC-3.1yr> BCAC-2.2 yr > BCAC-5.9 yr > CAC-3.1 yr. Bituminous coal AC performed the best over time. Endocrine disruptors such as these three compounds appear to be removed effectively by activated carbon through biodegradation and adsorption. Wood and coal based among the virgin ACs and 3.1 years used wood base among the used ACs appeared the lowest carbon usage rate(CUR) for nonylphenol removal by prediction model. Virgin and used coconut base ACs except BCAC had the lowest CUR for removal Bisphenol-A. Biodegradation of nonylphenol and Bisphenol-A did not occurred during the 9,800 bed volume experiment period. BCAC had the highest biodegradation capacity of 46% for amitrol among virgin ACs and the used coal based ACs had 33-44% higher biodegradation capacity than virgin's for amitrol so biodegradation is the effective removal technology for hydrophilic material such as amitrol.

• Advances in environmental research
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• v.9 no.2
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• pp.85-95
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• 2020

In this study, the decolorization of Evercion Blue P-GR (EBP) and Ostazin Black H-GRN (OBH) was investigated using white-rot fungi named as Trametes versicolor (T. versicolor) by Membrane Bioreactor (MBR) system. This study involved experiments employing synthetic textile wastewater in Membrane Bioreactor (MBR) system (170 ml), initially inoculated with a pure culture of fungi, but operated, other than controlling pH (4.5±0.2) and temperature (25±1℃), under non-sterile conditions. The effect of dye concentrations on fungal biodegradation was also investigated. The decolorization efficiencies were 98%, 90%, and 87% respectively, for EBP when the initial dye concentration of 50, 100, and 200 mg L^-1 were used. However, the decolorization percentages for OBH dye were obtained 95% for 50 mg L^-1 dye solution in 2 days and 66% for 100 mg L^-1 dye solution in 5 days. Possible interactions between dye molecules and the fungal surface were confirmed by SEM, EDX, and FTIR analyses.

• KSBB Journal
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• v.15 no.3
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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.

• Journal of Microbiology and Biotechnology
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• v.18 no.4
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• pp.767-772
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• 2008

Biodegradation of endocrine-disrupting phthalates [diethyl phthalate (DEP), dimethyl phthalate (DMP), butylbenzyl phthalate (BBP)] was investigated with 10 white rot fungi isolated in Korea. When the fungal mycelia were added together with 100 mg/l of phthalate into yeast extract-malt extract-glucose (YMG) medium, Pleurotus ostreatus, Irpex lacteus, Polyporus brumalis, Merulius tremellosus, Trametes versicolor, and T. versicolor MrP1 and MrP13 (transformant of the Mn-repressed peroxidase gene of T. versicolor) could remove almost all of the 3 kinds of phthalates within 12 days of incubation. When the phthalates were added to 5-day pregrown fungal cultures, most fungi except I. lacteus showed the increased removal of the phthalates compared with those of the non-pregrown cultures. In both culture conditions, p. ostreatus showed the highest degradation rates for the 3 phthalates tested. BBP was degraded with the highest rates among the 3 phthalates by all fungal strains. Only 14.9% of 100 mg/I BBP was degraded by the supernatant of P. ostreatus culture in YMG medium in 4 days of incubation, but the washed or homogenized mycelium of P. ostreatus could remove 100% of BBP within 2 days even in distilled water, indicating that the initial BBP biodegradation by P. ostreatus may be attributed to mycelium-associated enzymes rather than extracellular enzymes. The biodegradation rate of BBP by the immobilized cells of P. ostreatus was almost same as that in the suspended culture. The estrogenic activity of 100 mg/I DMP decreased during biodegradation by P. ostreatus.

• Journal of Environmental Science International
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• v.6 no.2
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• pp.153-163
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• 1997

In order to fad the most fitted biodegradation model, biodegradation kinetics model to the initial phenol and p-cresot concentrations were investigated and had been fitted by the linear regression. Bacteria capable of degrading p-cresol were isolated from soil by enrichment culture technique. Among them, strain Ml capable of degradillg p.rcresol has also degraded phenal and was identified as the genus Micrococcus from the results from of taxonomical studies. The optimal tonditlons for the biodegradation of phenal and p-cresol by Micrococcus sp. Ml were $NH_4NO_3$ 0.05%, pH 7.0, 3$0^{\circ}C$, respectively, and medium volume 100m1/250m1 shaking flask. iwicrococcus sp. Ml was able to grow on phenal concentration up to 14mM and p-cresol concelltration up to 0.8mM. With increasing substrate concentraction, the lag period increased, but the maximum specific growth rates decreased. The yield coefficient decreased with increasing substrate concentation. The biodegradation kinetics of phenol and p-cresol were best described by Monod with growth model for every experimented concentration. In cultivation of mixed substrate, p-cresol was degraded first and phenol was second. This result implies that p-cresol and phenol was not degraded simultaneously.