• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.197-200
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• 2003

In oil-contaminated environments, anaerobic biodegradation of toluene depended on the concentration and distribution of terminal electron acceptor as well as the physicochemical properties such as DO concentration, redox potential and pH. This study showed the anaerobic biodegradation of toluene in two different soils by using nitrate reduction, ferric iron reduction, sulfate reduction and methanogensis. Toluene degradation rates in the soil samples taken from rice filed and tidal mud flat by nitrate reduction were higher than those by other processes. Tho soil samples from the two fields were enriched for 130 days by providing toluene as a sole carbon source and nitrate or sulfate as a terminal electron acceptor. The toluene degradation rates in the enriched denitrifying consortia obtained from the rice field and tidal mud flat soil were 310.7 and 200.6 $\mu$mol$ L^{-1}$ / $d^{-1}$, respectively. The toluene (legradation rates in the enriched sulfate-reducing consortia from the fields ranged fi-om 149.1 to 86.1$\mu$mol $L^{-1}$ / $d^{-1}$ .

• 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.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.156-164
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• 1998

This study was performed to select media for the development of biological activated carbon process. Using activated carbon made by Norit, Calgon, Samchully Co., removal efficiency of humic acid by the isothermal adsorption test and biodegradation of organic matters by microbes attached to BAC and observation and counting of microbes attached to BAC were examined. The removal efficiency of humic acid with dose of activated carbon was influenced by initial concentration. Compared with other activated carbon, Norit was found to be most effective in view of adsorption capacity, biodegradation of organic matter, and attachment characteristics of microorganism. In conclusion, Norit which has high adsorption capacity and good biodegradation of organic matter was recommended for selecting media in BAC process.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.103-106
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• 2001

A remediation technology consisting of biodegradation and a modified Fenton reaction was developed to degrade mixtures of polycyclic aromatic hydrocarbons (PAHs) at a former manufactured gas plant (MGP) site. The original Fenton reaction (i.e., $H_2O$$_2$ + Fe$^{2+}$) was modified to be biocompatible by using ferric ions and chelating agents such as catechol and gallic acid. The modified reaction was effective in degrading PAHs at near neutral pH and thus was compatible with biodegradation. By the combined treatment of the modified Fenton reaction and biodegradation, more than 98% of 2- or 3-ring hydrocarbons and between 70 and 85% of 4- or 5-ring compounds were degraded in the MGP soil, while maintaining its pH about 6.6.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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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.

• Journal of the Korean Society of Industry Convergence
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• v.8 no.1
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• pp.5-10
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• 2005

PCL were intercalated into organically modified MMT (PCL-MMT) at $80^{\circ}C$ for 4hrs to prepare the PCL-MMT nanocomposite. PCL-MMT and PCL were mixed mechanically with two-roll mill at $150^{\circ}C$ for 15mins. From the results of XRD and TEM, it were found that PCL-MMT nanocomposite were prepared. And mechanical properties and biodegradation of nanocomposite have been investigated by tensile meter and biodegradability analysis experiment. Because of MMT dispersed homogeneously in PCL matrix, the Young's modulus of the nanocomposite was found to be excellent. But the tensile strength and elongation were decreased as increase of MMT. And MMT dispersed in PCL matrix was almost not affected on the biodegradation of PCL.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.340-343
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• 2003

Soils contaminated by hazardous hydrophobic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), have become a major environmental issue due to toxic and carcinogenic properties of those compounds. In this work, we investigated effects of various metabolic inducers on phenanthrene biodegradation. Biodegradation tests were peformed with two different Pseudomonads: Pseudononrdia hydrocarboxydans (Gram positive) and Pseudomonas putida (Gram negative). Intermediates of phenanthrene metabolism (1-hydroxy-2-naphthoate, salicylate, catechol, phthalate and protocatechuate) were selected as inducers. The tests indicated that 1-hydroxy-2-naphthoate was the most effective inducer and enhanced the phenanthrene degradation rate up to 5.7 times, even though all the others also had induction ability to some extent. The effective induction could be achieved even at a low concentration of 1-hydroxy-2-naphthoate. Addition of metabolic inducers would be an attractive trick for the successful bioremediation of PAH-contaminated soil.

• Journal of the Korean Applied Science and Technology
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• v.9 no.1
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• pp.31-40
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• 1992

This study is on the biodegradability of the activated sludge, which used to biodegrade Linear Alkylbenzene Sulfonate(LAS), synthetic detergents and sufactants. The activated sludge in waste water treatment plant is used to the test of biodegradation of anionic surfactants and nonionic surfactants, but it have the periodic change of the biological propety to the lapse of the time. For the puropse of controlling and adjusting of the activated sludge in biodegradation test, we collected microorganisms from the sewage plant and the soil, and then, made the activated sludge in semicontinuous aeration chamber. From determined biodegradation data, and the degree of biodegradability to the LAS, we confirmd the standardized synthetic activated sludge which have more stable biodegradability than the sewage activated sludge. In continuous biodegradation test, LAS(dodecene-1) was biodegraded more than 99%, In 7days by the standardized activated sludge.

• 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.