• Journal of Life Science
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• v.12 no.4
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• pp.416-422
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• 2002

Bacillus ehimensis YJ-37 was observed as a potential biological agent to control the occurrence of diseases and plant growth.promoting rhizobacteria (PGPR). Population density of B. ehimensis YJ-37 were higher 1.2~2 times in main roots and lateral roots than from nonrhizosphere soil and persisted around 10$^4$g root on the watermelon and radish root system upto 30 days after growing in pot condition. As a PGPR, B. ehimensis YJ-37 enhanced plant growth of watermelon and radish by soil treatment. The leaf area, hypocotyl length, root length and dry weight of radish were about 85, 33, 23 and 89% more than that of untreated plant, respectively. In case of watermelon were about 63, 27, 25 and 69% more than that of untreated plant, respectively. Biocontrol of damping-off in watermelon and radish caused by Rhizoctonia solani AG-4 and Pythium ultimum were carried out in pots using 3. ehimensis YJ-37. The results showed that might contribute to it's suppression of damping-off disease in field plants.

• 한국약용작물학회:학술대회논문집
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• 2011.09a
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• pp.396-397
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• 2011

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.08a
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• pp.140-141
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• 2005

• Korean Journal of Organic Agriculture
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• v.30 no.3
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• pp.409-422
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• 2022

Southern blight caused by Sclerotium rolfsii is a serious soilborne disease in economically important crops including pepper. In this study, we conducted a selection of antagonistic bacterial strains and organic materials to biologically control the disease. Out of 39 strains isolated from soils at Jinju in Korea, strain JJ2-01 showed the highest mycelial growth inhibition; garlic oil among various organic materials significantly reduced disease incidence and severity. When a combination of strain JJ2-01 and garlic oil, or each was drenched into the pepper plants, combined treatment and garlic oil significantly suppressed the disease development, however, acid phosphatase activity in garlic oil-treated plants decreased. In the case of combined treatment, the soil activities did not affect by treatment, while soil urease activity was significantly increased by the combined treatment. Therefore, given soil quality and health for sustainable agriculture, the combination of strain JJ2-01 and garlic acid was an effective application for environmental-friendly control of Southern blight in pepper plants.

• Microbiology and Biotechnology Letters
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• v.2 no.2
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• pp.63-77
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• 1974

The optimal operation problem of enzyme reactor of double inhibitions are dealt with Maximum Principle and Steepest Ascent Method. The operation policy of the intial concentration and amount of substrate, reaction time and the method of cross feed of substrate are determined in a system of reactor of constant volume add with cross feed of substrate. The policy for the soluble enzyme and the immobilized enzyme are greatly different from each other, and the performance index, the profit per unit time, of the latter are nearly twice greater than that of the former.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.50-56
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• 2001

Thirty-three bacterial and fungal strains were isolated from the rotten soybeans and soybean sprouts to isolate pathogenic microorganisms which cause soybean sprouts rot during soybean sprouts cultivation. In pathogenicity tests of the isolates on soybean sprouts, two isolates(K-17 and K-28) caused soybean sprouts rot and were identified as Erwinia carotovora and Fusarium sp., respectively. To isolate antagonists aganist K-17 and K-28 pathogens, bacteria were isolated from various soybean-cultivated soils and screened by the inhibition zone method. A bacterial isolate(J-232) which inhibited growth of both pathogens was identified as Pseudomonas fluorescens and further examined. The culture filtrate of P. fluorescens J-232 (dilution rate of 500 times) inhibited the growth of Erwinia carotovora K-17 and Fusarium sp. K-28 both on potato dextrose agar medium and on soybean sprouts cultivated in vessel. The development of soybean sprouts rots was observed during cultivation by inoculation of soybean seeds with culture filtrate of both pathogens. The combined inoculation of soybean seeds with culture filtrate of antagonistic bacterium and that of pathogens prevented soybean sprouts rot, and the growth of soybean sprouts was similar to that of control. The soybean sprouts inoculated with antagonists culture filtrate alone did not develop soybean sprouts rot, and the growth of the seedlings was shown to be slightly promoted as compared with that of control.

• Proceedings of the Korean Society of Life Science Conference
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• 2002.03a
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• pp.110-110
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• 2002

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.187-197
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• 1987

Bacteria and fungi antagonistic to Fusarium oxysporum f. sp. cucumerinum Owen were effectively isolated with each of modified Triple Layer Agar (TLA) technique from rhizosphere soil where cucumber had been grown healthily in plastic film house. Three predominant bacterial isolates selected were identified as Pseudomonas fluorescens, and P. putida, Serratia sp. and three fungal isolates were Gliocladium sp. Trichoderma harzianum, and T. viride. Antagonistic bacteria inhibited $26-45\%$ of germination and $41-56\%$ of germ tube elongation of microconidia of F. oxysporum f. sp. cucumerinum on Water Agar (WA). P. fluorescens was the strongest inhibitor. Several my co parasitisms were observed on dual culture of WA between antagonistic fungi and F. oxysporum f. sp. cucumerinum such as coiling, penetration, overgrowing, and lysis. Mycelial lysis of the pathogen was the most severe at pH 4.6, followed by 3.6, 5.6 and 6.6 of the medium in decreasing order. At pH 6.6, mycelia of the pathogen were not conspicuously damaged, however, the antagonistic fungi formed abundant chlamydospores especially Gliocladium sp. T. harzianum revealed the most excellent antagonism in vitro.

• Current Research on Agriculture and Life Sciences
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• v.17
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• pp.7-13
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• 1999

Thirty bacteria were isolated from the red pepper rhizosphere. The isolates were screened for antagonism to Alternaria alteranta causing red pepper black rot. Antagonistic bacterium No. J-24 was selected among the isolated bacteria and was identified as Bacillus subtilis based on morphological and physiological characteristics and MIDI system. B. subtilis J-24 showed antifungal activities against A. alternata(inhibition percentage, 99%), Botrytis cinerea, Phytophthora capsici, Pythium ultimum, Colletotrichum gloeosporioides, Stemphylium botryosum. The growth of red pepper seedling was promoted as compared to control when the microbial inoculants was mixed in bed soil. In the mixed microbial inoculants bed soil, the leaf area of red pepper was increased of 15 percent, the hypocotyl weight 12 percent, the root length 12 percent, total dry weight 13 percent as compared to those grown in the general bed soil.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.335-343
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• 1992

A Streptomyces strain No. 182-27, which produced amino acid antimetabolite, was isolated from soil. During the course of screening for new amino acid antimetabolites from the culture broths of Actinomycetes, we found that the strain produced a substance active against Gram-positive bacteria and its activity was reversed by L-Ieucine on the synthetic minimal agar medium in the culture broth. The morphological and cultural characteristics serve to identify the producing organism strain 182-27 as the Streptomyces, although the species of this strain should be resolved in further studies. Fermentation was carried out in the synthetic medium at $28^{\circ}C$ for 78 hours. The fermentation yield reached about 2 mg per liter of the broth. Purification was done by ion exchange resin, active carbon, silica gel column chromatography and obtained 20 mg of pure active substance from the 20 $\ell$ culture broth. The 182-27 substance was obtained as white powder, mp 18SoC. From the physicochemical characteristics of the substance, it was amino acid like substance but unknown about its chemical structure. It is active against some Gram-positive bacteria and reversed by L-Ieucine.