• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.10a
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• pp.89-110
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• 2003

The limitations of conventional soil and groundwater contamination remediation technologies have motivated a search for innovative technologies; particularly in situ technologies that do not require extraction of contaminants from the subsurface. All engineered in situ remediation systems require that the contaminant be mixed with a remedial compound. Horizontal flow treatment wells (HFTWs), an innovative technology that consists of a pair of dual-screened treatment wells, were used at a trichloroethylene (TCE) contaminated site to efficiently achieve this mixing of contaminant and remedial compound in order to effect in situ bioremediation (McCarty et al., 1998). In this paper, the potential of HFTWs to treat chlorinated aliphatic hydrocarbons (CAHs) as well as other soil and groundwater contaminants of concern, such as nitroaromatic compounds (NACs), perchlorate, and methyl-tert-butyl ether (MTBE), is examined. Through a combination of laboratory studies, model analyses, and field evaluations, the effectiveness of this innovative technology to manage these contaminants is investigated.

• Journal of Environmental Science International
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• v.17 no.5
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• pp.479-484
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• 2008

The application of microwave technology has been investigated in the remediation of diesel-contaminated soil. The paper deals with economic assessment by means of cost analysis and degradation characteristics at different microwave powers for total petroleum hydrocarbon (TPH) in diesel contaminated soils. The soils from S Mountain around the D University were sampled. The samples were screened with 2.0 mm mesh and dried for 6 hours before the diesel was added into the dried soils. The diesel-contaminated soil (3,300 mg THP/kg soil) was prepared with diesel (S Co.). The drying process was carried out in a microwave oven, a standard household appliance with a 2,450 MHz frequency and 700 W of power. The experiments were conducted from 0 to 20 minutes as the microwave powers increased from 350W to 500W to 700W. The concentrations of TPH were analysed using a gas chromatography/mass spectrometer (GC/MS). The initial concentration of TPH was 3,300 mg TPH/kg soil. The weight of contaminated soil was 200g. The concentration of TPH was decreased to 1,828 mg TPH/kg soil (44.7%), 1,347 mg TPH/kg soil (59.2%) and 1,014 mg TPH/kg soil (69.3%) at 350W, 500W and 700W for 15 minutes respectively. In addition, the curve was best fit with first order kinetics using the least-square method. The ranges of a first order rate constant k and r-square were $0.0298{\sim}0.0375min^{-1}$ and $0.9373{\sim}0.9541$ respectively.

• YAKHAK HOEJI
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• v.39 no.6
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• pp.585-592
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• 1995

Soil microorganisms producing immunomoduators that can restore ultraviolet B (UVB) radiation-induced suppression of the immune response were screened in vitro. Exposure of freshly isolated murine epidermal cells (EC) to $180{\;}J/m^{2}$ of UVB radiation resulted in approximately 90% impairtnent of accessory cell function, as measured by their ability to support anti-CD3 monoclonal antibody-induced T-cell mitogenesis. When the culture supenmtants of 150 actinomycete strains were exanuned for their capacity to prevent or repair the UVB-induced impairment of accessory cell function, 4 of them were identified to contain immunomodulators that can restore the decreased accessory cell finiction. The soil isolate that showed the most effective restorative activity, G40025. was selected and fturther characters Addition of 10.mu.l of the culture supernatant of G40025 grown in G-media to cultures of UVB-irradiated EC right after UVB-irradiation restored the decreased accessory cell function by 58%. The immunomodtdator produced by G40025 appeared to be stable at 100.deg. C for 10 min. Taxonomical studies by cultural, morphological, and physiological characterization showed that the soil isolate, G40025, belongs to the genus Streptomyces.

• The Plant Pathology Journal
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• v.36 no.3
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• pp.231-243
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• 2020

Rice blast, caused by Magnaporthe oryzae, is one of the most destructive rice diseases worldwide. The aim of this study was to screen bacterial isolates to efficiently prevent the occurrence of rice blast. A total of 232 bacterial isolates were extracted from nonrhizospheric rice soil and were screened for antifungal activity against M. oryzae using a leaf segment assay. Strains S170 and S9 showed significant antagonistic activity against M. oryzae in vitro and in leaf disk assays, and controlled M. oryzae infection under greenhouse conditions. The results showed that strains S170 and S9 could effectively control rice leaf blast and panicle neck blast after five spray treatments in field. This suggested that the bacterial strains S170 and S9 were valuable and promising for the biocontrol of rice disease caused by M. oryzae. Based on 16S rDNA, and gyrA and gyrB gene sequence analyses, S170 and S9 were identified as Bacillus amyloliquefaciens and B. pumilus, respectively. The research also demonstrated that B. amyloliquefaciens S170 and B. pumilus S9 could colonize rice plants to prevent pathogenic infection and evidently suppressed plant disease caused by 11 other plant pathogenic fungi. This is the first study to demonstrate that B. amyloliquefaciens and B. pumilus isolated from nonrhizospheric rice soil are capable of recolonizing internal rice stem tissues.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.958-963
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• 2008

A series of experiments were conducted to assess the effectiveness of rhizobacteria containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase for growth promotion of peas under drought conditions. Ten rhizobacteria isolated from the rhizosphere of different crops (peas, wheat, and maize) were screened for their growth promoting ability in peas under axenic condition. Three rhizobacterial isolates, Pseudomonas fluorescens biotype G (ACC-5), P. fluorescens (ACC-14), and P. putida biotype A (Q-7), were selected for pot trial on the basis of their source, ACC deaminase activity, root colonization, and growth promoting activity under axenic conditions. Inoculated and uninoculated (control) seeds of pea cultivar 2000 were sown in pots (4 seeds/pot) at different soil moisture levels (25, 50, 75, and 100% of field capacity). Results revealed that decreasing the soil moisture levels from 100 to 25% of field capacity significantly decreased the growth of peas. However, inoculation of peas with rhizobacteria containing ACC deaminase significantly decreased the "drought stress imposed effects" on growth of peas, although with variable efficacy at different moisture levels. At the lowest soil moisture level (25% field capacity), rhizobacterial isolate Pseudomonas fluorescens biotype G (ACC-5) was found to be more promising compared with the other isolates, as it caused maximum increases in fresh weight, dry weight, root length, shoot length, number of leaves per plant, and water use efficiency on fresh and dry weight basis (45, 150, 92, 45, 140, 46, and 147%, respectively) compared with respective uninoculated controls. It is highly likely that rhizobacteria containing ACC deaminase might have decreased the drought-stress induced ethylene in inoculated plants, which resulted in better growth of plants even at low moisture levels. Therefore, inoculation with rhizobacteria containing ACC deaminase could be helpful in eliminating the inhibitory effects of drought stress on the growth of peas.

• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.41-47
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• 1998

The purpose of this research is evaluation of adsorption capacity of the cast for TCE comparing with the yellow clay. Furthermore, the experimental data was fitted with the Langmuir and Freundlich isotherm and was found to be apllicable to the adsorption isotherm equation. The soil bed reactor used in this study was made of glass(10 cm in diameter, 100 cm in depth). The cast and yellow clay used as adsorbents were screened with 8-20 mesh mecanically. Results from Equilibrium test with adsorbents showed that the equibrium time of the cast and yellow clay was 9min independent of the amount of the adsorbents. The adsorption efficiencys of the cast and yellow clay for TCE was 66.3% and 56.2%, respectively. In the application of Freundlich isotherm, 1/n of the cast and yellow clay were 0.786 and 0.704, respectively. These results showed that the cast was more available than the yellow clay as TCE adsorbent. The best adsorption capacity was showed at 0% moisture content, 70 ppm inlet concentration and 25$^{\circ}$C temperature.

• Mycobiology
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• v.28 no.4
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• pp.190-192
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• 2000

Antifungal bacteria for biological control of plant diseases or production of novel antibiotics to plant pathogens were isolated in 1997 from various soils of Ansung, Chunan, Koyang, and Paju in Korea. Sixty-four bacterial strains pre-screened from approximately 1,400 strains were tested on V-8 juice agar against eight plant pathogenic fungi using in vitro bioassay technique for inhibition of mycelial growth. Test pathogens were Alternaria mali, Colletotrichum gloeosporioides, C. orbiculare, Fusarium oxysporum f. sp. cucumerinum, F. oxysporum f. sp. lycopersici, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. A wide range of antifungal activity of bacterial strains was found against the pathogenic fungi, and strain RC-B77 showed the best antifungal activity. Correlation analysis between inhibition of each fungus and mean inhibition of all eight fungi by 64 bacterial strains revealed that C. gloeosporioides would be best appropriate for detecting bacterial strains producing antibiotics with potential as biocontrol agents for plant pathogens.

• Korean Journal of Organic Agriculture
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• v.12 no.1
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• pp.101-114
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• 2004

This study was carried out to clarify the effects of antagonistic microorganism, Bacillus sp. JC181 isolated from the greenhouse soil grown cucumber plants on the growth inhibition of plant pathogen, fusarium wilt (Fusarium oxysporum) occurred in cucumber plants in greenhouse. Antagonistic bacterial strains were isolated and were investigated into the antifungal activity of the antagonistic microorganism against fusarium wilt. Screened fourteen bacterial strains which strongly inhibited F. oxysporum were isolated from thc greenhouse soil grown cucumber plants, and the best antagonistic bacterial strain designated as JC181, was finally selected. Antagonistic bacterial strain JC181 was identified to be the genus Bacillus sp. based on the morphological and biochemical characterization. Bacillus sp. JC181 showed 58.2% of antifungal activity against the plant pathogen growth of F. oxysporum. By the bacterialization of culture broth and heated filtrates of culture broth, Bacterial strain, Bacillus sp. JC181. showed 91.2% and 260% of antifungal activity against F. oxysporum, respectivrly.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.679-686
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• 2010

Mechanical characteristics of bottom ash produced in coal-fired power plant are investigated to utilize as light-weight fill materials. Triaxial compression test, water retention test, and unsaturated direct shear test were conducted for weathered soil (WS), reclaimed bottom ash (RBA), and screened bottom ash (BA). RBA had larger frictional angle and lower effective cohesion than those of WS. Water retention charactersitics of RBA and BA existed within distributions of soil-water characteristic curves for domestic weathered soils. Unsaturated shear strength of RBA was similar to that of WS at matric suctions of 50 kPa and 100 kPa. As a conclusion, bottom ash can be used as fill materials to replace the conventional construction materials by.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.877-880
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• 1999

Over 50 morphologically distinctive soil Streptomyces were isolated from various Jocations in the Yongin area in Korea and visually screened for dye-decoloring activities on an agar plate. Two Streptomyces species (AD001 and ND002) showed strong dye-decoloring activities on the plate containing congo-red and new-fuchin dyes, respectively. Also, the liquid culture supernatants of these species showed 2,4-dicholophenol (DCP) oxidation activities only in the presence of hydrogen peroxide, a characteristic of Actinomycetes lignin-peroxidase (ALiP)-P3 isoform found in dye-degrading S. viridosporus T7A and S. badius 252. Based on their dye-decoloring capabilities and the 2,4-DCP oxidation kinetic data, it is suggested that these Streptomyces secrete not-yet-characterized extracelluar enzyme(s), whose activities are very similar to the ALiP-P3 enzyme.