• The Korean Journal of Mycology
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• v.41 no.4
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• pp.218-224
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• 2013

Of 1,100 yeast strains which were isolated from various Korean fermented foods, screened for phosphate solubilization, five strains showed the ability to solubilize tricalcium phosphate. The 26S rDNA domain D1-D2 sequence analysis revealed the identification of strain Y393 and Y524 as Pichia anomala (99.8 and 100% identity, respectively), Y669 as Pichia farinosa (100% identity), Y901 as Candida versatilis (100% identity), and Y1101 as Pichia subpelliculosa (100% identity). All the phosphate solubilizing strains showed mesophilic characteristics. The temperature range for growth of 4 strains was $20{\sim}35^{\circ}C$ and P. farinosa Y669 was able to grow up to $45^{\circ}C$. The strain C. versatilis Y907 was able to grow at pH range of 5.0~6.0 and showed halophilic characteristics with tolerance to 15% of NaCl concentration. The Phosphate solubilizing yeast strains were survived well in bed soil for 8 weeks which were maintained densities of $10^7{\sim}10^8$ cfu/g. The highest phosphate solubilizing activity was observed in P. subpelliculosa Y1101. It solubilized 697.2 ug/mL of phosphorus from tricalcium phosphate with decrease in pH from 6.8 to 4.37 after 11 days of inoculation.

• The Korean Journal of Mycology
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• v.41 no.4
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• pp.261-267
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• 2013

In order to select antagonists for biological control of downy mildew of cucumber, 126 bacteria were isolated from cucumber plants collected from several locations in Korea. Among them, Five isolates were selected as potential biocontrol agents of cucumber downy mildew using a leaf disc bioassay method. In preventive and curative effect tests, the isolate CC110 was found to be effective to control downy mildew on cucumber showing diseased area by 0% whereas that of control was 15.0~18.0%. A bacterium isolate CC110 was identified as Bacillus amyloliquefaciens subsp. plantarum based on phylogenetic analysis using gyrB gene sequence. The culture liquid of isolate CC110 in TSB media were more effective for the control of the disease than those cultured in LB, NB, and KB media in leaf disk bioassay. when undiluted liquid, two-fold, five-fold diluted culture broth, and undiluted liquid, two-fold, five-fold diluted filtrate of isolate CC110 in TSB media were treated, diseased area of cucumber powdery mildew were 0%, 3.0%, 8.0%, 0%, 4.0% and 7.0%, respectively, whereas diseased area in the control was 21.0%. In the cucumber seedling tests, when the culture broth of isolate CC110 in TSB media was treated, diseased area were 35.0%, whereas that of control was 82.0%. When B. amyloliquefaciens CC110 was treated four times at five-day interval in the vinylhouse test, the control effect of cucumber downy mildew was higher than that treated three at seven-day interval.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.319-328
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• 1995

This study was carried out to investigate the resistance mechanism by three different kinds of procymidone-resistant and susceptible isolates of Botrytis cinerea which had been collected from green houses. The average resistance level of the resistant strains was 1,000 times higher than that of susceptible ones. Also, it was revealed that the resistance was not originated from components excreted by Botrytis cinerea, based on the result obtained from the treatment with piperonyl butoxide and triphenyl phosphate as an inhibitor of monooxygenase and esterase, respectively. The total lipod content of resistant strains was 1.3 times higher than that of susceptible ones, among fatty acids, palmitic acid, stearic acid, and linoleic and being 3.0, 2.5, and 2.0 times higher, respectinely. Also slight differences in sterol contents and components were observed. The crude chitin content was slightly higher in susceptible strains but contents of N-acetyl glucosamine, a hydrolysate of chitin, were about 2 times higher in resistant ones.

• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.41-46
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• 2011

A galactose-fermenting yeasts, Saccharomyces cerevisiae No. 9, was selected by screening their abilities to produce carbon dioxide gas when grown on galactose. The selected strain, No. 9 and the reference strains NRRL Y-1528 which was exceptionally resistant to high concentration of substrate, were acclimated on sugars such as glucose, mannose, and galactose, and then their ethanol productivities were investigated during fermentation on these three carbon sources. Ethanol productivity of the strain No. 9 reached to the maximum levels after 18 h of fermentation and the ethanol yield was from 36 to 38% when presented as $[EtOH]_{max}/[Sugar]_{ini}(g/g)$, regardless of the conditions of acclimation. From the results obtained by acclimation and fermentation, it was concluded that the ethanol yields from galactose were not affected by the sugars acclimated. Improvements of the strain S. cerevisiae No. 9 were attempted to increase the fermentation efficiency and/or ethanol yields on high concentration of substrate by the conventional mutation methods employing methanesulfonic acid, ethyl ester (EMS). Mutants, Mut-5 (SJ1-40), -17 (LK4-25) and -24 (LK2-48) fermented galactose at the concentration of 20% in the levels of higher 39.9~51.6% than the mother strain, No. 9, however, their ethanol yields never exceeded those of the reference strain.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.341-345
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• 2007

Fifty endophytic bacteria, which produced slime around the colonies, were isolated from Pueraria roots. In particular, HDN-14, TDG-3, and TNB-3 strains, which appeared to be high viscosity producers, were selected. These strains produced high levels of polysaccharides in Puerara root medium extract. The purified polysaccharide was digested with 1N HCI and analyzed by HPLC, with glucose ($45.6{\sim}63.1%$), maltose ($14.6{\sim}23.7%$), and fructose ($17.4{\sim}23.7%$) detected as constitutive sugars. When determined by the homology relationship of the 16S rDNA sequence with the relative taxa, the HDN-14 and TNB-3 strains were closely ($99.06{\sim}99.32%$) related to the Pseudomonas $koreensis^T$ and Pseudomonas $jessenii^T$, while TDG-3 were closely ($99.48{\sim}99.74%$) related to Pseudomonas $plecoglossicida^T$, Pseudomonas $mosselii^T$, and Pseudomonas $monteilii^T$. The major cellular Pseudomonas acids are $3OH-C_{10:0}$, $2OH-C_{12:0}$, $3OH-C_{12:0}$, and $3OH-C_{12:1}$, with these strains being further differentiated in species belonging to the genus Pseudomonas.

• The Korean Journal of Mycology
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• v.16 no.2
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• pp.79-86
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• 1988

Interspecific fusion products were obtained from fusion of Ganoderma applanatum and Ganoderma luridum. Frequency of fusion was 0.77-1.38%. Fusion products were selected by the comparision of morphology and color of colony. Fusion Products had chracteristics of two parental strains and generally grew faster than the parents. Some fusants were segregated on GCM. Fusion products were confirmed by mycelial morphology and electrophoretics pattern of esterase isozyme from mycelium. Most of fusion products were lack in clamp connection but those fusion products, that were segregated produced mycelium with and without clamp connection. Some of the fusion products produced fruit body on sawdust medium.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.359-365
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• 2010

Fifty Actinobacteria strains were isolated from rhizosphere soil of Sasa borealis. In the course of screening for antibacterial activity against bacterial leaf spot of pepper (Xanthomonas axonopodis pv. vesicatoria) of isolates, 12 isolates showed strong antibiotic activity. Basis on the 16S rRNA gene sequence, they were belonging to Streptomyces cluster II. Strain JR-24 exhibited strong antibiotic activity against X. axonopodis pv. vesicatoria, had a minimum inhibitory concentration of 10 ${\mu}l$/disc. The strain JR-24 was most closely related to Streptomyces galbus $DSM40089^T$ (98.1%), Streptomyces longwoodensis $LMG20096^T$ (98%) and Streptomyces capoamus $JCM4734^T$ (97.8%). When assayed with the API 20NE and 50 CHE kit, it is positive for utilization of L-arabinose, D-fructose, D-glucose, D-galactose and hydrolysis of gelatin, protein, starch. The strains contained iso-$C_{14:0}$ (25.93%), iso-$C_{15:0}$ (10.13%), anteiso-$C_{15:0}$ (19.29%) and iso-$C_{16:0}$ (20.35%) as major fatty acids and MK-9 (H4), MK-9 (H6), and MK-9 (H8) as the isoprenoid quinone. Strain JR-24 was suggested new species of genus Streptomyces by nearest neighbors of genotypic relationships and phenotypic characterization. This study was important to microbial resources investigation for environment-friendly agriculture.

• Microbiology and Biotechnology Letters
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• v.43 no.1
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• pp.56-64
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• 2015

It has been known for some time to the wine industry that non-Saccharomyces yeasts play an important role in increasing volatile components through the secretion of extracellular enzymes. The objective of this study was to investigate what types of enzymes are produced by 1,007 non-Saccharomyces yeast strains isolated from Korean fermented foods. Among 1,007 yeast strains, the 566, 45 and 401 strains displayed β-glucosidase, glucanase and protease activity, respectively. In addition, the 563 and 610 strains possessed tolerances against cerulenin and TFL, and the 307 strain was tolerant to 15% ethanol. Yeasts producing harmful biogenic amines and hydrogen sulfide were excluded from further study, and eventually 12 yeast strains belonging to the genera Wickerhamomyces, Hanseniaspora, Pichia, Saccharomyces were identified, based on the 26S rRNA gene sequences. Among the 12 strains, the 9 and 5 strains possessed glucose and ethanol tolerance, respectively. Yeasts belonging to the genus Saccharomyces produced more than 8% alcohol, but non-Saccharomyces yeasts produced only 3% alcohol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.10
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• pp.1216-1224
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• 2017

Acetic acid bacteria strains were isolated from commercial natural vinegar. Ten isolated strains were identified using 16S rRNA gene sequencing data after evaluating the ethanol- and sulfur-tolerance. Eight of the strains isolated were identified as Acetobacter pasteurianus. A. pasteurianus JAC002, JAC005, and JAC008 strains, which showed a high ethanol tolerance, were selected for making "Makgeolli seed-vinegar". Rice wine vinegars were manufactured with the selected strains through fermentation, and their physicochemical properties and antimicrobial activities were evaluated. A. pasteurianus JAC002 strain showed the highest oxidation ability to acetic acid from ethanol on the twentieth day of fermentation, resulting in 4.21% total acidity, 3,791.77 mg% acetic acid content, and 2,931.78 mg% ethanol consumption content. Rice wine vinegar manufactured with the A. pasteurianus JAC002 strain showed increased antimicrobial activities against Staphylococcus aureus (KACC1927) and Escherichia coli (KACC10115). As a result, A. pasteurianus JAC002 strain was found to be the most suitable strain for "Makgeolli seed-vinegar".

• The Korean Journal of Mycology
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• v.38 no.1
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• pp.69-74
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• 2010

The 2 strains of Pleurotus ostreatus showing very severe and mild symptom of brown blotch were selected, and their F1 hybrid strains were made by mating of their single spore isolates. Hydrophobicity of fruiting body surface and brown blotch severity of the parental and their 11 F1 hybrid strains showing different level of severity of brown blotch were determined. Correlation coefficient (R) between disease severity and hydrophobicity were 0.68 and 0.70 on two independent experiments. Correlation coefficient between disease severity and disease incidence that was determined in the oyster mushroom farm were 0.46 and 0.52 on two independent experiments. When GFP-tagged Pseudomonas tolaasii was monitored with confocal microscope on cap surface of fruiting body, more cells of the pathogen were clustered on the severe strain than the mild strain, which indicates that the bacterial pathogen proliferates more on the severe strain. These results suggest that hydrophobicity of oyster mushroom fruiting body affects disease severity of the brown blotch disease; the longer the bacterial suspension stays on fruiting body surface more severe symptom of the blotch develops.