• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.603-613
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• 2019

This study was carried out to examine the antagonistic effect against phytopathogenic fungi of isolated strains from soil samples collected from Busan, Changwon, and Jeju Island: Botrytis cinerea, Colletotrichum acutatum, Corynespora cassiicola, Fusarium sp., Rhizoctonia solani, Phytophthora capsici, and Sclerotinia sclerotiorum. According to results of our studies, isolated strains showed an antagonistic effect against phytopathogenic fungi. Such an antagonistic effect against phytopathogenic fungi is seen due to the production of siderophores, antibiotic substances, and extracellular amylase, cellulase, protease, and xylanase enzyme activities. Extracellular enzymes produced by isolated strains were significant, given that they inhibited the growth of phytopathogenic fungi by causing bacteriolysis of the cell wall of plant pathogenic fungi. This is essential to break down the cell wall of plant pathogenic fungi and thus help plant growth by converting macromolecules, which cannot be used by the plant for growth, into small molecules. In addition, they are putative candidates as biological agents to promote plant growth and inhibit growth of phytopathogenic fungi through nitrogen fixation, indole-3-acetic acid production, siderophore production, and extracellular enzyme activity. Therefore, this study suggests the possibility of using Bacillus subtilis ANGa5, Bacillus aerius ANGa25, and Bacillus methylotrophicus ANGa27 as new biological agents, and it is considered that further studies are necessary to prove their effect as novel biological agents by standardization of formulation and optimization of selected effective microorganisms, determination of their preservation period, and crop cultivation tests.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.525-531
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• 2004

A strain antagonistic to Fusarium solani, CHO104, was selected from approximately 100 microorganisms isolated from soil. Strain CHO104 was identified as Bacillus amyloliquefaciens and found to be Gram-positive based on the Biolog system and 16S rRNA methods. A culture broth of B. amyloliquefaciens CHO104 also exhibited antimicrobial activity against various microorganisms. As such, the EtOAc extract of the culture broth was isolated by various column chromatographic procedures and HPLC. The antimicrobial and antifungal substance was then characterized as macrolactin A $(C_{24}H_{34}O_5)$ using high-resolution EI-MS and NMR analyses, and found to be very effective in inhibiting the growth of Staphylococcus aureus, E. coli, and Botrytis cinerea, even when using a concentration of one-twentieth of the benzoic acid as the control compound.

• Journal of Soil and Groundwater Environment
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• v.20 no.4
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• pp.15-21
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• 2015

Anaerobic biodegradation of diesel with coexisting heavy metals (Pb) was monitored in batch mode. Two different groups of the indigenous bacteria from a site contaminated with diesel and lead were used in this research: the first group was composed of a single species and the second group was composed of several species. The effect of heavy metals on the microbial population was monitored and confirmed the biodegradation mechanism in each combined contaminant. Growth of the microorganisms in 21 days was observed Diesel > Diesel + Pb > Diesel + Cu > Diesel + Pb + Cu > Diesel + Cr > Diesel + Pb + Cr. Indigenous microorganisms showed the adaptation in the Pb contaminate. Interactive toxic effect using AMES test observed larger synergistic effect than antagonistic in Diesel + Cr and Diesel + Pb + Cr. Therefore, the main effects of diesel biodegradation in the present of heavy metals are likely to exist other factors as well as toxic of heavy metals. This is a necessary part of the future studies.

• Journal of the Korean Society of Food Culture
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• v.26 no.2
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• pp.190-197
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• 2011

Chungtaejeon is a traditional tea introduced in the age of the Three States and is the only "Don-cha" culture in the world that survived on the southwestern shore of Korea. To restore Chungtaejeon and to make the tea with consistent quality, the microorganisms involved in traditional type fermentation of Chungtaejeon were isolated, and the tea was prepared with high fermentation ability starters. The sensuous characteristics of Chungtaejeon were also examined. Only Bacilli were found in 3 and 5 year aged Chungtaejeon samples. The Lactobacilli were isolated from properly fermented kimchi and one of them showed high growth capability in media containing green tea extract and also showed strong antagonistic activity against methicillin-resistant Staphylococcus aureus, S. aureus, Salmonella, and E. coli. It was identified and named Lactobacillus plantarum CHO25. Chungtaejeon was fermented with a single starter of L. plantarum CHO25 and with a mixed starter (L. plantarum CHO25, Saccharomyces cerevisiae and Bacillus amyloliquefaciens CHO104). The single fermented sample had the highest cell growth after 5 days of inoculation and the level decreased slowly thereafter. The mixed fermented sample showed strong growth of S. cerevisiae. The highest hunter values were the a value of the single fermented sample and the b value of the mixed sample. The single fermented tea showed the best incense score.

• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.229-237
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• 1987

In order to study the biological control of soil-borne disease of sesame, antagonistic isolates of Trichoderma , Bacillus sand streptomyces to Fusarium oxysporum and Rhizoctonia solani were isolated from the rhizosphere soils of sesame plants and some other habitats. Out of the isolates of microorganisms collected a strain of Trichoderma viride was selected as a biological control agent for the study and its effect on the control of damping-off and the seedling growth of sesame was investigated. The results obtained are as follows: 26 percents of Bacillus spp. isolated from the rhizosphere soil of sesame plants showed antagonism to two pathogenic fungi. Important species were B. Subtilis and B. polymyxa. Streptomyces species isolated from the rhizosphere soils of sesame lysed the cell wall of hyphae and conidia of F. oxysporum and reduced conspicuously the formation of macroconidia and chlamydospores of the fungus. 84 percents of Trichoderma spp. isolated from the rhizosphere soil of sesame plants were antagonistic to F. oxysporum and 60 percents of the isolates were antagonistic to both F. oxysporum and R. solani. Trichoderma viride TV-192 selected from antagonistic isolates of Trichoderma spp. was highly antagonistic to F. oxysporum and soil treatment with the isolate reduced notably damping-off of sesame. T. viride TV-192 showed better growth in crushed rice straw, barley straw and sawdust media than F. oxysporum. Sawdust was selective for the growth of T. viride. Supplementation of wheat bran and mixtures of wheat bran and sawdust inoculated with T. viride TV-192 in the soil reduced remarkably damping-off of sesame by F. oxysporum but high density of the fungus TV-192 caused the inhibition of seed germination and seedling growth of sesame. Inhibitory effects of Trichoderma species on seed germination and seedling growth of sesame were different according to the isolates of the fungus. Normal sesame seedlings on the bed treated with the fungus showed better growth than not treated seedlings.

• The Plant Pathology Journal
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• v.27 no.4
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• pp.333-341
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• 2011

Two antifungal bacteria were selected from forest soils during the screening of microorganisms antagonistic to Cylindrocarpon destructans, a cause of ginseng root rot. The antifungal bacteria were identified as Bacillus subtilis (I4) and B. amyloliquefaciens (yD16) based on physiological and cultural characteristics, the Biolog program, and 16S rRNA gene sequencing analyses. Antagonistic activity of both bacterial isolates to C. destructans increased with increasing temperature. More rapid starch hydrolytic activity of the bacteria was seen on starch agar at higher temperatures than at lower temperatures, and in the higher density inoculum treatment than in the lower density inoculum treatment. The bacterial isolates failed to colonize ginseng root the root tissues inoculated with the bacteria alone at an inoculum density of $1{\times}10^6$ cfu/ml, but succeeded in colonizing the root tissues co-inoculated with the bacteria and C. destructans. Scanning electron microscopy showed that the pathogen was damaged by the low-density inoculum treatment with the bacterial isolates as much as by the high-density inoculum treatment. Both bacterial isolates were more effective in reducing root rot when they were treated at a concentration of $1{\times}10^6$ cfu/ml than at $1{\times}10^8$ cfu/ml. Also, only the former treatment induced prominent wound periderm formation, related to structural defense against pathogen infection. The results suggest that the bacterial antagonists may have high potential as biocontrol agents against ginseng root rot at relatively low-inoculum concentrations.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.421-428
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• 2003

To develop the functional-compost containing antifungal substance by using antagonistic microorganisms, Spinacia oleracea L and Rhizoctonia solani Kuhn O-28 were used as a model plant and phytopathogen, respectively. Total 80 strains were isolated from the compost of various waste foods mixture processed for a year. Among them, No.15-2 strain was selected due to its highest antifungal activity against R. solani Kuhn O-28 and was identified phyno- and phylogenotypically as Burkholderia cepacia genomovar V. which is rare probability in pathogen, by 16S rDNA sequencing and specific primer pair PCR method. B. cepacia No.15-2 preferentially dominated during the compost and its cell numbers were maintained almost $${\times}$10^{13}$ cuf/g for 15 days. The morbidity caused by R. solani Kuhn O-28 in S. oleracea L cultivation was reduced to 40% by addition of B. cepacia No.15-2. In conclusion, the antifungal compost using B. cepacia No.15-2 could be applied to biocontrol of various crops blights caused by fungal pathogen.

• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.252-257
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• 2007

This study was carried out to clarify the effects of antifungal Streptomyces sp. isolated from the soil grown kiwifruit on the growth inhibition of fruit rot (Botryosphaeria dothidea) infected in kiwi fruit plants in the southwestern districts of Jeonnam. Two hundred and fifty microorganisms were isolated and examined into the antifungal activity against Botryosphaeria dothidea. We screened and isolated six bacterial strains which have a strong inhibition against Botryosphaeria dothidea. And the best antifungal strain designated as the strain #120 showing 96.0% antifungal activity against Botryosphaeria dothidea was finally selected. The strain #120 was identified as Streptomyces sp. #120 based on its morphological, physiological, biochemical and chemotaxonomic characteristics.

• Journal of Technologic Dentistry
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• v.22 no.1
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• pp.145-152
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• 2000

In order to select an effective antibiotic substance against oral resident bacteria, we were isolated from soil and texonomically analyzed. Seven hundred and eighteen strains were isolated on humic acid- vitamin agar(HV agar) and 220 strains were on methanol medium from three each paddy forest, field and riverside soil samples. So, during the screening of antibiotics from soil, we isolated microorganisms showing powerful antagonistic activity against oral resident bacteria. Microorganism was tested against 25 strains of bacteria, yeast and fungi. Among them, No. 248 strain exhibited the most strongly growth inhibition. So, the taxonomical analysis the isolated strain was found to be unknown Actinomyces sp. and was named No 248. A production of the antibiotics from No. 248 begins at the early exponential phase developed at the 72th hour under the optinum conditions. The property of No. 248 antimicrobial compound was very stable under acid(pH 3.0) and alkali(pH 10.0) treatment, but it was instable in heat treatment at $120^{\circ}C$. For the improvement of antibiotic activity, two mutants were isolated from strain No. 248 by the treatment of mutagenic agents, NTG and hydroxylamine. As a result, the mutant strains excreted the potent antibiotics to inhibit the growth of Candida albicans.

• Korean Journal of Environmental Agriculture
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• v.23 no.1
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• pp.68-74
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• 2004

Miscanthus purpurascens Juice containing potassium (37,952 mg/L), nitrogen (14,000 mg/L), phosphorus (6,800 mg/L), magnesium (5,969 mg/L), calcium (5,910 mg/L), etc., was investigated to develop a novel meidum far the mass cultivation of useful microorganisms. For this research, we first isolated an antagonistic bacterium G-74 from soil, which showed strong growth inhibition against two phytopathogenic fungi, Rhizoctonia solani and Botrytis cinerea, and identified as Bacillus lentimorbus G-74 based on the morphological characteristics and MIDI analysis. Culture conditions for G-74 strain in the M. purpurascens juice medium were optimized. Dilution rate of the medium, temperature and initial pH for the optimum growth of G-74 strain were 30% (V/V), $35^{\circ}C$ and 5.0, respectively. It was found that additions of 2.0% (W/V) corn starch as a carbon source and 1.0% (W/V) yeast extract as a nitrogen source in this medium increased B. lentimorbus G-74 growth to 66% more efficient than Luria Bertani medium.