• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1074-1081
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• 2006

As common pollutants in surface and groundwater, nitrate nitrogen($NO_3-N$) and trichloroethylene(TCE) can be chemically and biologically reduced by zero valent iron(ZVI) and peat soil. In batch microcosm experiments, chemical reduction of TCE and nitrate was supported by hydrogen from ZVI. For biological degradation of TCE and denitrification peat soil was introduced. ZVI reduced TCE, while peat provided TCE sorption site and microbes performing biological degradation. Nitrate reduction was also achieved by hydrogen from ZVI. In addition, indirect evidence of denitrification was observed. More reduction of TCE and nitrate was achieved by ZVI+peat treatment however nitrated reduction was hindered in the presence of TCE in the system due to the competition for hydrogen. TCE reduction mechanism was more dependent on ZVI, while nitrate was peat-dependent. Hydrogen and methane concentration showed that peat had various anaerobic denitryfing and halorespiring bacteria.

• Korean Journal of Environmental Agriculture
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• v.40 no.4
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• pp.345-352
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• 2021

BACKGROUND: Salinity is one of the major limiting factors in agriculture that affect the growth and productivity of crops. It is economically difficult to artificially purify the soil affected by salt. Therefore, the use of plant growth-promoting bacteria (PGPB) in an effort to reduce stress caused by salt is emerging as a cost-effective and environment-friendly method. In this study, the purpose was to isolate the salt-tolerant bacteria from the rhizosphere soil and identify their ability to promote plant growth under salt stress condition. METHODS AND RESULTS: The isolates KST-1, KST-2, AST-3, and AST-4 that showed plant growth-promoting activity for barley in salt conditions were close to Bacillus cereus (KST-1, KST-2, and AST-4) and Bacillus thuringiensis (AST-3) and showed high salt tolerance up to 7% of additional NaCl to the media. When inoculated to barley, the strains had only minor effect on the length of the barley. However, the concentrations of chlorophyll in the barley leaves were found to be higher from the bacteria-inoculated pots than those from the uninoculated control. In particular, the chlorophyll concentration in Bacillus cereus AST-4 experiment was 5.45 times higher than that of the uninoculated control under the same experimental condition. CONCLUSION(S): The isolated salt-tolerant bacteria were found to influence on chlorophyll concentration of the barley. As represented by the strain AST-4, microbes may suggest a cost-effective and environmentally benign method to alleviate salt stress of crops cultivated in salt-accumulated soils such as reclaimed lands.

• Research in Plant Disease
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• v.26 no.4
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• pp.202-209
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• 2020

Organic farming is necessary to sustainable agriculture, preserve biodiversity and continued growth the sector in agriculture. In organic farming, reduced usage of chemical agents that adversely affect human health and environment, employing amino acids and oil cake fertilizer, plant extracts, and microbial agents are used to provide safe agricultural products to consumers. To investigation microbiome structure, we proceeded on the pepper plant with difference fertilizers and treatments in organic agriculture for three years. The microbial communities were analyzed by the next generation sequencing approach. Difference soil microbiota communities were discovered base on organic fertilizer agents. Occurrences of virus and anthracnose diseases had a low incidence in conventional farming, whereas bacteria wilt disease had a low incidence in microbial agents treated plots. Microbe agents, which applied in soil, were detected in the microbial community and the funding suggested the applied microbes successfully colonized in the organic farming environment.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.517-524
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• 2014

As an assessment of substantial equivalence and environmental risks of branchless chrysanthemum GM lines (LeLS69, LeLS76, LeLS80) developed in Korea, we investigated their degree of branchlessness and developmental characteristics including growth and flowering, as well as the stability of populations of insect pests and soil microbes. The GM lines were compared with a control variety, 'Jinba'. LeLS80 showed the highest level of branchlessness among the three GM lines, whereas abnormal axillary buds developed in lines LeLS76 and LeLS69. There were no significant differences between the growth characteristics of 'Jinba' and the GM lines. The branchlessness LeLS80 was increased during the summer season, suggesting that it is a useful germplasm for developing elite branchless cultivars. These GM lines showed no significant differences in the occurrence of five insect pests including aphids, mites, leaf miners, thrips, and whiteflies. Similarly, for soil microbes including bacteria and actinomycetes, there were no significant differences between 'Jinba' and the GM lines. However, there was a higher occurrence of fungi in the GM lines compared to 'Jinba'. Our findings suggest that 'Jinba' and the GM lines are substantially equivalent, although further monitoring studies are needed to confirm this.

• Journal of Life Science
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• v.19 no.5
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• pp.676-679
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• 2009

In order to produce a new antibiotic material against Jurkat T cells using horizontal gene transfer among microbes, co-cultures between soil bacteria AY2000 and the multiple antibiotic producer S. griseus was carried out. It showed that the highest active substance against Jurkat T cells was produced at 48 hr of co-culture time with MTT assay. Moreover, a morphological change of nuclear of Jurkat T cells treated with co-cultured substance was observed in DAPI staining. This result suggests that a new material was produced with co-culture supernatant, and that co-culture between microboes can develop new antibiotic materials.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.563-566
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• 2000

In order to obtain microbial endochitosanase for enzymatic production of chitooligosaccharides from chitosan, we screened four microbes from soil and selected. Bacillus sp. HSB-21 which showed highest activity. Chitosanase, produced from isolating microbe, was endo-type and molecular mass of the enzyme was estimated as 21,000 by active staining. Its optimum pH and temperature were 5.5 and $50^{\circ}C$, respectively. It was stable in the pH range of 3.0 to 8.0 and up to $40^{\circ}C$. It did not produce chitomonosaccharide and produced chitooligosaccharide ranging from chitobiose to chitooctaose as major end-products from chitosan. The chitosanase from Bacillus sp. HSB-21 can be applicable to enzymatic production of chitooligosaccharide which has high degree of polymerization .

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.247-251
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• 2008

Degradation behavior in the seawater of Tongyeong, Incheon, Kunsan and Hongsung was explored for Mater-Bi$^{(R)}$, poly(3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV), poly(butylene succinate-co-butylene adipate) (PBSA) and polycaprolactone (PCL) which can eventually be used for various fishery tools. Acinetobacter lwoffu/junii and Shewanella algae/putrefaciens inhabited all the seawater samples. Eikenella corrodens was also detected in all the seawater samples, although identified with poor confidence by VITEK system. Mater-Bi$^{(R)}$ was degraded faster than PHBV, PBSA and PCL in the seawater in contradiction to the degradation behavior in soil environment. The seawater retrieved from Incheon exhibited the most elevated activity for the plastic degradation, which may be partly ascribed to the largest number of total viable counts.

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.223-232
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• 1985

To find microorganisms of producing $\alpha$-amylase inhibitors, actinomycetes were isolated from soil samples that were collected at different locations in Korea and screened for enzyme inhibitory activity. A strain of these microbes had a high inhibitory activity and was identified as one of the genus Streptomyces by morphological, biochemical and physiological studies according to the methods of the International Streptomyces Project (ISP). The medium used consisted of 3 ％ corn starch, 0.2％ yeast extract and 0.8％ peptone (pH 7.0). When this strain was aerobically cultured in the medium on a rotary shaker, the highest inhibitory activity was obtained after four days. This inhibitor had inhibitory activities on various $\alpha$-amylases and glucoamylase, but not on $\beta$-amylase.

• YAKHAK HOEJI
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• v.47 no.2
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• pp.85-92
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• 2003

Seok-jeong (SJ) is a solution of various metal ions and numerous other organic substances produced through extraction and fermentation of herbs and soil using geo-microbes, and it has been shown to improve symptoms of senile dementia. In this study, we investigated the protective effects of SJ against neurotoxicity of cadmium in HT22 hippocampal neuron cell line. SJ significantly protected from the cadmium-induced decreased cell viability measured by MTT assay (p＜0.01). The protective effects of SJ against cadmium toxicity were confirmed through observing morphological changes using inverted microscope. Additionally, SJ significantly repressed the formation of lipid peroxidation induced by high concentration of cadmium, and likewise, significantly repressed the reduction of glutathione by cadmium in HT22 cells. Vitamin C at the concentration found in SJ did not show any protective effect against cadmium toxicity in HT22 cells, indicating that vitamin C may not have a major role in the protective mechanism of SJ. Taken together, these results suggest that SJ may be a valuable agent for the protection of cadmium toxicity on the neuronal cells, and that the mechanism of the action of SJ may be due to reduced lipid peroxidation and increased glutathione level.

• Environmental Engineering Research
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• v.19 no.3
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• pp.185-195
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• 2014

Despite the enormous technical and economic efforts to improve environmental conditions, currently about 40% of the global population (or 2 billion people) are still lack access to safe water supply and adequate sanitation facilities. Pollution problems and transmission of water- related diseases will continue to proliferate. The rapid population growth and industrialization will lead to a reduction of arable land, thus exacerbating the food shortage problems and threatening environmental sustainability. Natural systems in this context are a transdisciplinary approach which employs the activities of microbes, soil and/or plants in waste stabilisation and resource recovery without the aid of mechanical or energy-intensive equipments. Examples of these natural systems are: waste stabilisation ponds, aquatic weed ponds, constructed wetlands and land treatment processes. Although they require relatively large land areas, the natural systems could achieve a high degree of waste stabilisation and at the same time, yield potentials for waste recycling through the production of algal protein, fish, crops, and plant biomass. Because of the complex interactions occurring in the natural systems, the existing design procedures are based mainly on empirical or field experience approaches. An integrated kinetic model encompassing the activities of both suspended and biofilm bacteria and some important engineering parameters has been developed which could predict the organic matter degradation in the natural systems satisfactorily.