• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.327-330
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• 1996

Poly(L-leucine)(PLL)/poly(ethylene oxide)(PEO)/poly (L-leucine)(PLL) block copolymers were synthsized by polymerization of L-leucine N-carboxyanhydride with diamine-terminated PEO for possibility of wound dressing which may have several advantages such as 1) increase of solubility, 2) control of biodegradation, 3) absorption of body fluid. 4) non-immunogenic effect than PLL homopolymer wound dressing aleady commercialized. Water content increased with an increase of PEO content in the block copolymer due to the hydrophilicity of PEO. Release of silver sulfadiazine(AgSD) from AgSD loaded wound dressing increased with an increase of PEO content in the block copolymer. It was found that the number of Pseudomonas aeruginosa decrease with an increase of PEO content due to the fast release of antibacterial agents with an increase of PEO content in the block copolymer.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.06a
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• pp.53-60
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• 1998

The effect of chemically oxidized intermediated of PAH compounds on the degradation of the parent PAHs was characterized and evaluated for the context of cooxidation. Anthracene and pyrene exhibited extensive degradation (mean percent removal of 57.5%) after 28 days of incubation by introducing the Fenton oxidation intermediate of the PAH compounds, while unoxidized anthracene and pyrene exhibited 12.5% removal. Dehydrogenase activities for the oxidized PAH studies ware enhanced two to five folds to the unoxidized PAHs studies. The chemical oxidation products can serve as a structually very similar analogue substrates for a consortia of soil microorganisms and as a metabolic intermediates in the biodegradation sequence of the parent PAH compounds. These results may be interpreted in the context of cooxidation mechanism whereby high recalcitrant PAH compounds are biodegraded in the soil and suggest a potential tool for bioremediation of PAHs contaminated soils and protection of groundwater.

• Journal of Soil and Groundwater Environment
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• v.21 no.2
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• pp.22-28
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• 2016

In order to evaluate landfill stabilization based on organic carbon, stoichiometric analysis and a biological methane potential (BMP) test based on modeling were performed at the 2^nd Sudokwon Landfill Site. Mass balance analysis through a BMP test proved to be more adaptable for evaluation, and it showed that 28.9% of landfill organic carbon was expected to remain by 2046, 30 years after landfill closure. The organic carbon ratio of total landfill waste for 2046 is forecasted as 2.9% in demolition waste and 5.1% in household waste, and, if one were to consider plastic as an organic waste, the ratios would increase to 15.9% and 28.3%, respectively. Therefore, it seems that organic matter biodegradation facilitating measures such as bioreactor landfill technology and preemptive recovery of combustible waste are necessary to shorten post closure management periods and to meet the landfill stabilization guidelines more safely.

• Journal of Soil and Groundwater Environment
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• v.20 no.2
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• pp.32-40
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• 2015

Laboratory column experiments were conducted to evaluate the feasibility of injectable apatite method for the sequestration of Sr-90 in groundwater. The columns were tested to evaluate the rate of citrate biodegradation, the amounts of apatite formed, and the treatability of strontium by the sediment and apatite. The results showed the decreases in citrate, calcium, and phosphate concentrations and the increases in alkalinity and citrate degradation products (acetate and formate) in the columns, suggesting that the citrate degradation and formation of calcium phosphate are occurring. Although the calcium and phosphate were not completely consumed within the columns, some amounts of apatite were formed and it showed an ability to treat strontium in groundwater. This study provides a fundamental understanding of reaction mechanisms for the injectable apatite sequestration method for Sr-90 removal.

• Journal of Microbiology
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• v.41 no.1
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• pp.7-15
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• 2003

Nine dichlorprop-degrading bacteria and three pairs of bacteria showing syntrophic metabolism of the herbicide were isolated from soils, and their genetic and phenotypic characteristics were investigated. Analysis of 16S rDNA sequences indicated that the isolates were related to members of the genera, Sphingomonas, Herbaspirillum, and Bradyrhizobium. Twelve different chromosomal DNA patterns were obtained by polymerase-chain-reaction (PCR) amplification of repetitive extragenic palindromic (REP) sequences from the 15 isolates. The isolates were able to utilize the herbicide dichlorprop as a sole source of carbon and energy and their dichlorprop derogative pathways were induced by the presence of dichlorprop. Most of the isolates and syntrophic pairs were able to degrade both (R)- and (S)-dichlorprop, but strain DP522 exhibited enantioselective degradation of (S)-dichlorprop. The isolates degraded 2,4-dichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid , and mecoprop, in addition to dichlorprop. Oxygen uptake experiments indicated that most of the isolates degraded dichlorprop through 2,4-dichlorophenol.

• Korean Journal of Microbiology
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• v.22 no.2
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• pp.97-101
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• 1984

To investigate the biodegradation pattern of rice straw, mainly composed of cellulose, hemicellulose and lignin components, by the isolate stran Bacillus subtilis $DO_4$, the change of cell population was observed on CMC (carboxymethyl cellulose), larch wood xylan and lignosulfonate as a carbon source respectively. Also, the transition pattern of enzyme activities of cellulase and xylanase and lignin contents was measured on rice straw and mixed substrate according to growth. The results in these experiments revealed that xylanase activity was first appeared and cellulase activity in the next, while lignin component was almost not changed through the culture period.

• Korean Journal of Microbiology
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• v.23 no.4
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• pp.241-247
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• 1985

The objectives of this study were to isolate and identify ninhydrin positive substande(s) produced in the culture broth of Pseudomonas fluorescens. It was found that the NPS could stimulate bioconversion of furfural into furoic acid. In order to isolate the NPS from the culture broth, cell free filtrate was subjected to ion-exchange chromatography, gel-permeation and finally to cellulose column chromatography. The purified NPS was white amorphous power and very soluble in water, slightly soluble in methanol and very insoluble in organic solvents. UV, and IR absorption spectra. $^H$ and $^{13}C-NMR$ were measured in order to identify the chemical structure of the NPS.

• Korean Journal of Microbiology
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• v.24 no.1
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• pp.51-56
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• 1986

Eight strains of the bacteria capable of growing on salicylate as the sole carbon source were isolated form soil and river water. Three of these isolates were identified as Acinetobacter calcoaceticus (AcBl), Pseuomonas putida biotype B (PpB2), and P. putida biotype A (PpB3). Effects of temperature, pH and C source concentration on biodegradation of salicylate by PpB3 were wxamined. The optimum conditions were as follows; $30^{\circ}C$ for temperature, 7.0 for pH, and 10mM for C source concentration. Ultraviolet scanning spectrum of the salicylate was measured. The spectrum has two peaks at 225nm and 292nm. The spectra of the culture filtrates indicate that ring degradation of salicylate is accomplished.

• Journal of Microbiology
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• v.35 no.3
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• pp.193-199
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• 1997

From several industrial wastewaters, 14 bacterial strains which degrade benzene, toluene, o-xylene, m-xylene, or p-xylene (BTX) were obtained. These strains were characterized as to their species composition and the substrate range, kinetic parameters and the substrate interactions were investigated. Although BTX components have a similar chemical structure, isolated strains showed different substrate ranges and kinetic parameters. None of the strains could degrade all of BTX components and most of them showed an inhibition (Haldane) kinetics on BTX, BTX mixtures were removed under inhibitory substrate interactions with variation in the intensity of inhibition. For a complete degradation of BTX, a defined mixed culture containing three different types of patyways was constructed and all of the BTX components were simultaneously degraded with the totla removal rate of 225.69 mg/g biomass/h Judging from the results, the obtained mixed culture seems to be useful for the treatment of BTX-contaminated wastewater or groundwater as well as for the removal of BTX from the contaminated air stream.

• Journal of Life Science
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• v.5 no.1
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• pp.8-19
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• 1995

The Optimal condition for degradation of crystal violet and other triphenylmethane dyes by Citrobacter sp. SK-3 isolated from the activated sludge of dye manufacturing factory was investigated. The optimal culture medium for the degradation of triphenylmethane dye was composed of minimum inorganic salt medium supplemented with 0.5% galactose, 0.1% beef extract, with the initial pH of 8.0 to 9.0. Under this condition, Citrobacter sp. SK-3 degraded 200 ppm of crystal violet completely within 24 hours. Citrobactre sp. SK-3 also degraded efficiently malachite green, pararosaniline, brilliant green, methyl violet, basic fuchsin and methyl red. Analysis of the degradation products of crystal violet through this layer chromatography and high performance liquid chromatography indicated that the methyl groups bound to crystal violet backborn were gradually demethylated to pentamethyl-, tetramethyl- and trimethylpararosaniline.