• Journal of Microbiology
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• v.35 no.1
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• pp.66-71
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• 1997

To investigate the biodegrading capability of several white-rot fungi isolated in Korea, biodegradation of BTX (benzene, toluene, xylene), phenanthrene and pyrene were tested in fungal cultures. Phanerochaete chrysosporium removed 20-30% of BTX mixture during 21 days of incubation in serum bottle. Coriolus versicolor KR-11W and Irpex lacteus mineralized 10.02 and 8.26% of totla phenanthrene, respectively, which were higher than in other studies with P. chrysosporium. These two strains also showed high mineralization rates (9.2-10.1%) for 4-ring pyrene. I. lacteus metabolized most of the added pyrene and 23.29% was incorporate dinto fungal biomass. Almost 50/5 of the pyrene was converted to polar metabolites and recovered from aqueous phase of culture. These results indicated that some white- rot fungi have higher biodegradability than P. chrysosporium and could be used in bioremediation of aromatic hydrocarbon contaminants in soil.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.7-12
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• 2001

Three Pseudomonas strains (Bk8, Bk9, Bk10) selected from soil for their ability to degrade herbicide diuron were tested for their heavy metal resistance. The growth of these catabolic strains on a minimal medium with various concentrations of $Cd^{2+},\;Zn^{2+},\;Ni^{2+}$, and $Hg^{2+}$ revealed a minimal effect on the carbon source for the inhibitory effect of the metals. One of these strains, namely, Bk8, exhibited a high resistance to the heavy metals as compared to the two other strains. This strain harbors plasmid pBk8 (110 kb) and contains at least fur determinants encoding heavy metal resistance. Nickel and zinc resistance are encoded by genes located on the chromosome, while cadmium and mercury resistance are on plasmid pBk8. Accordingly, the characteristics of strain Bk8 suggest that it would be useful in the bioremediation of aromatic compounds in the presence of toxic heavy metals as co-contaminants.

• Journal of Soil and Groundwater Environment
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• v.21 no.5
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• pp.8-15
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• 2016

Bioremediation, which uses microbes to degrade most organic pollutants in soil and groundwater, can be used in solving environmental issues in various polluted sites. In this research, a wind-driven bioventing system is built to degrade about 20,000 mg/kg of high concentration diesel pollutants in soil-pollution mode. The wind-driven bioventing test was proceeded by the bioaugmentation method, and the indigenous microbes used were Bacillus cereus, Achromobacter xylosoxidans, and Pseudomonas putida. The phenomenon of two-stage diesel degradation of different rates was noted in the test. In order to interpret the results of the mode test, three microbes were used to degrade diesel pollutants of same high concentration in separated aerated batch-mixing vessels. The data derived thereof was input into the Haldane equation and calculated by non-linear regression analysis and trial-and-error methods to establish the kinetic parameters of these three microbes in bioventing diesel degradation. The results show that in the derivation of μ_m (maximum specific growth rate) in biodegradation kinetics parameters, K_s (half-saturation constant) for diesel substance affinity, and K_i (inhibition coefficient) for the adaptability of high concentration diesel degradation. The K_s is the lowest in the trend of the first stage degradation of Bacillus cereus in a high diesel concentration, whereas K_i is the highest, denoting that Bacillus cereus has the best adaptability in a high diesel concentration and is the most efficient in diesel substance affinity. All three microbes have a degradation rate of over 50% with regards to Pristane and Phytane, which are branched alkanes and the most important biological markers.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.96-100
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• 2004

Chlorothalonil is a wide-spectrum fungicide that is widely used in the world. Chlorothalonil is known as a potential toxic pollutant due to its high application rate, persistence, and toxicity to humans and other species. With the Increase of necessity of bioremediation, this study was conducted to isolate the chlorothalonil dissipation bacteria from soil. Soil samples were collected from 184 sites of farmland and wastewater disposal soil.661 strains resistant to chlorothalonil were isolated by dilution method from chlorothalonil-containing enrichment culture. After incubating at $30^{\circ}C$ in 1/10 LB media containing 10 ppm of chlorothalonil for a week, dissipation ability of chlorothalonil was investigated by HPLC. Finally, a strain SH35B, capable of dissipating chlorothalonil efficiently, was selected. The strain SH35B was identified as Ochrobactrum sp. Ten ppm of chlorothalonil In 1/10 LB media were completely dissipated by the growth of Ochrobactrum sp. SH35B for 30 h at $30^{\circ}C$. In the isolated strain, the content of glutathione and the activity of glutathione S-transferase were supposed to be ones of the Important factors for chlorothalonil dissipation and were higher than those of control strains, Escherichia coli and Bacillus subtilis.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.287-292
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• 2002

Lignin-peroxidase (LiP) has been considered as one of the most important industrial enzymes for biodegradation of various recalcitrant toxic compounds such as chlorinated aromatic hydrocarbons and azo-dyes. Recently, several soil actinomycetes have been reported to secrete a functionally-similar lignin-peroxidase called actinomycetes lig-nin-peroxidase (ALiP). In this manuscript, we isolated over 100 morphologically distinct actinomycetes from the contaminated soils around 10 different gas stations located nearby the Kyung-An river. Among these actinomycetes screened based on the congo-red dye-decolorization activities, one newly-isolated actinomycetes named SMA-2 showed the most significant dye-decoloring activity on the congo-red plate as well as a significant ALiP activity in a yeast-extract-malt-extract liquid media supplemented with starch. The optimum SMA-2 culture condition fur ALiP production was determined and the kinetic parameters fur the SMA-2 AkIP activity were characterized. The optimally-cultured SMA-2 also exhibited the oxidation activities toward various recalcitrant aromatic compounds including phenol, 2- chlorophenol, 4- chlorophenol, 2,4- dichlorophenol ,2,6- dichlorophenol, and 2,4, f-trichlorophe - not, suggesting a potential application of SMA-2 for contaminated soil bioremediation.

• Journal of Korea Soil Environment Society
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• v.4 no.1
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• pp.13-23
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• 1999

In this research, 3-hydroxypyridine(2-HP) metabolic ability of starving Arthrobacter crystallopoietes cell and the effect of humic acid on the metabolism of this starving cell were evaluated. 2-HP metabolic ability of exponential phase cell (acclimated cell) was much higher than that of lag phase cell (unacclimated cell) during starvation period. After 3 days of starvation, 2-HP half-life of the acclimated cell was 14 hours and that of the unacclimated cell was 46.5 hours. Humic acid enhanced the stability of 2-HP monooxygenase of starving co]1 and, after 2 days of starvation, the residual activity rate of this enzyme of the microbial cell starved in humic acid solution was 12% while the rate for control condition was 1.5%. After 14 days of starvation, 2-HP half-life for control condition was 43 hours and that for humic acid condition was 1.25 hour.

• Journal of Soil and Groundwater Environment
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• v.21 no.1
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• pp.94-103
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• 2016

Landfarming that supplies aerobic biodegradation condition to indigenous microbes in soils is a biological remediation technology. In this research, volatilization and biodegradation rate by indigenous microbes in the soil contaminated with total petroleum hydrocarbons (TPH) were measured. Soils were contaminated with diesel artificially and divided into two parts. One was sterilized by autoclave to remove indigenous microorganism and the other was used as it was. Various moisture contents and number of tillings were applied to the soil to find out proper condition to minimize volatilization and enhance bioremediation. Volatilization of TPH was inhibited and biodegradation was enhanced by increase on moisture content. Tilling was usually used to supply air for microbes, but tillings did not affect the growth of microbes in our study. Enough moisture content and proper aeration are important to control volatilization in landfarming. Also, TPH degradation was a function of the microbe counts (x₁), numbers of tilling (x₂), and moisture content (x₃) from the application of the response surface methodology. Statistical results showed the order of significance of the independent variables to be microbe counts > numbers of tilling > moisture content.

• Microbiology and Biotechnology Letters
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• v.52 no.1
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• pp.44-54
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• 2024

One of the serious modern environmental problems is pollution caused by highly toxic pesticides. Only small amounts of applied pesticides reach their target, and the rest ends up in soil and water. Chlorpyrifos is a toxic, broad-spectrum organophosphate insecticide. In humans, chlorpyrifos inhibits acetylcholinesterase (AChE) in the peripheral and central nervous system, and particularly in children, small amounts of this pesticide cause neurotoxic damage. As the toxic effects of chlorpyrifos and its persistence in the environment require its removal from contaminated sites, it is essential to study the biological diversity of chlorpyrifos-degrading microorganisms. In this study, we sought to determine the chlorpyrifos-degrading ability of the bacterial strain Ochrobactrum intermedium PDB-3. This strain was isolated from soil contaminated with various pesticides and identified as PDB-3 based on morpho-cultural characteristics, MALDI-TOF MS, and 16S rRNA. Studies were conducted for 30 days in sterile soils containing initial concentrations of 50, 75, 100, and 125 mg/kg of chlorpyrifos. To determine the degradation of chlorpyrifos, a liquid culture of the strain was added to the soil at three optical densities: 0, and after 24 and 48 h (OD = 0.03, 0.2 and 0.32). Using GX-MS, we determined that chlorpyrifos was converted to 3,5,6-trichloro-2-pyridinol (TCP). We also found that with increasing optical density, rapid degradation of the initial concentration of chlorpyrifos occurred. Sterile soil without strain PDB-3 was used as a control sample.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.335-339
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• 2010

A diesel-degrading bacterium, Gordonia sp. SD8, was isolated from soil contaminated with petroleum, and its diesel degradation was characterized in a soil as well as a liquid culture system. SD8 could grow in the mineral salt medium supplemented with diesel as a sole carbon and energy source. The maximum specific growth rate ($0.67{\pm}0.05\;d^{-1}$) and diesel degradation rate ($1,727{\pm}145$ mg-TPH $L^{-1}\;d^{-1}$) of SD8 showed at 20,000 mg-TPH $L^{-1}$ and $30^{\circ}C$, and then this bacterium could degrade high strength of diesel of 40,000 mg-TPH $L^{-1}$. The residual diesel concentration in the inoculated soil with SD8 was 3,724 mg-TPH kg-dry $soil^{-1}$ after 17 days, whereas the diesel concentration in the non-inoculated soil was $8,150{\pm}755$ mg-TPH kg-dry $soil^{-1}$. These results indicate that Gordonia sp. SD8 can serve as a promising microbial resource for the bioremediaion of contaminated soil with petroleum hydrocarbons including diesel.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.210-217
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• 2011

In an effort to isolate novel bacteria for the bioremediation of over-fertilized soils, we identified 135 denitrifying cells out of 3,471 oligotrophic bacteria pools (3.9%) using a denitrification medium supplemented with potassium nitrate as the sole nitrogen source. Soil samples were taken from ecologically well-conserved areas, including a mountain swamp around the demilitarized zone (Yongneup), two ecoparks (Upo and the Mujechi bog), and ten representative islands around the Korean peninsula (Jejudo, Daecheongdo, Socheongdo, Baekryeongdo, Ulrungdo, Dokdo, Geomundo, Hongdo, Huksando and Yeonpyeongdo). All of the 135 bacteria produced nitrogen gas from the denitrification medium, and were proved to be nitrate reductase positive by API-BioLog tests. Phylogenetic analysis using 16S rDNA sequences revealed that the 135 bacteria consisted of 44 different genera. Along with the most prominent, Proteobacteria (87.4%), we identified denitrifying bacteria from Firmicutes (9.4%), Actinobacteria (2.4%), and Bacteroidetes (0.8%). Physiological analyses of the 44 representative denitrifying bacteria, under various pH levels, growth temperatures and salt stresses, revealed 12 favorable denitrifying strains for soil bioremediation.