• Journal of the Korean Society of Food Culture
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• v.35 no.5
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• pp.450-458
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• 2020

This study examined the optimal temperature and time conditions to maintain high quality Dongchimi during the fermentation and storage period. Dongchimi was fermented at low (5℃), medium (10 and 15℃), and high (20℃) temperatures until the acidity reached 0.2, 0.3, and 0.4%. respectively. From the consumer's preference test enrolling five consumers, Dongchimi fermented at 15℃ until an acidity of 0.3% (for approximately six days) was evaluated to be the optimal status because of its high score of overall acceptance, taste, and odor of consumers. To determine the optimal storage temperature of fermentation, Dongchimi was stored at three different temperatures (-1, 2, 5℃) for four weeks after fermenting at 15℃ for six days. During the storage period, most of the physicochemical properties (pH, acidity, reducing sugar content, and organic acid) and microbiological properties changed significantly in the 2 and 5℃ groups, resulting in a significant change in descriptive sensory analysis of Dongchimi. These results indicate that fermentation at 15℃ and storage at -1℃ for Dongchimi enables it to maintain the best quality for a long time.

• Journal of fish pathology
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• v.20 no.3
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• pp.237-247
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• 2007

In 1999, Vibrio harveyi infection occurred among cultured marine finfishes including olive flounder (Paralichthys olivaceus), black rockfish (Sebastes schlegeli), and turbot (Scophtalmus maximus) in the province of Gyeongsang, Korea. We examined the various microbiological characteristics of this V. harveyi strains. V. harveyi was grown well in the 3% NaCl at 30℃. The swarming activity appeared to be an one of the characteristic properties of the V. harveyi was the highest in the 2% NaCl concentration at TSA medium. These cells were elongated and had the several lateral flagella which is not waved and shorter than polar flagella. It was not luminescent in the all isolated strains. Whole cell of the V. harveyi had a major protein of 50 kDa and presented various band around of 40 kDa in strains.

• Journal of Life Science
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• v.20 no.3
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• pp.403-410
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• 2010

In order to produce high-quality fermenting composts, a microorganism was isolated from the natural world. The bacterium has not only in high enzyme activities but also had good antimicrobial activities against phytopathogenic microorganisms. Its cultivating characteristics were then investigated. Bacterium KJ-9, which contains high CMCase, protease and chitinase activities and excellent antimicrobial activities against phytopathogenic microorganisms, was separated from leaf mold and identified as Bacillus licheniformis by two methods: Bergey's Manual of Systematic Bacteriology and API 50 CHL Carbohydrate Test Kit (Bio Merieux, France) using an ATB (Automated Identification) computer system (Bio Merieux, France). Optimal medium for cultivation of B. licheniformis was 2% soluble starch as a carbon source, 0.5% yeast extract as a nitrogen source and 0.05% $MgSO_4{\cdot}7H_2O$. Optimal growth conditions of pH, temperature and shake speed were pH 7.0, $50^{\circ}C$ and 180 rpm, respectively. Culture broth of B. licheniformis KJ-9 cultured for 36~60 hr was effective in fungicidal activities against plant pathogens including Botrytis cinerea, Corynespora cassicola, Fusarium oxysporum, and Rhizoctonia solani.

• The Korean Journal of Mycology
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• v.51 no.1
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• pp.39-49
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• 2023

This study aimed to screen and investigate the microbiological characteristics, enzyme activity, and physiological functionality of unrecorded wild yeasts from the Wolsung valley of South Deogyu mountain and Jinjamcheon in Daejeon city, Korea. Candida sorboxylosa WSC25-4 (NNIBRFG47336), Arxula adeninivorans WSC6-3 (NNIBRFG47335), Farysizyma taiwaniana JRC6-2 (NNIBRFG47339), Saturnispora dispora JTS19-1 (NNIBRFG47334), Vanderwaltozyma polyspora JJCH5-3 (NNIBRFG47337), and Vanrija fragicola SW-9 (NNIBRFG47338) have not been previously recorded. None of these formed spores or pseudo-mycelium, and four strains, including C. sorboxylosa WSC25-4, were global in shaped. Except for V. polyspora JJCH5-3, all strains grew well in the yeast extract-peptone-dextrose (YPD), potato-dextrose and yeast malt extract media. A. adeninivorans WSC6-3 and S. dispora JTS19-1 grew well in 40% glucose-containing YPD medium and V. fragicola SW-9 in 5% NaCl-containing YPD medium. The supernatant of A. adeninivorans WSC6-3, F. taiwaniana JRC6-2, and V. fragicola SW-9 exhibited 58.0, 59.0, and 59.0% of glucoamylase activity, respectively. C. sorboxylosa WSC25-4 also produced extracellular alkaline protease. Antioxidant activity of the supernatant from F. taiwanian JRC6-2 was high (79.8%), while the other five unrecorded yeasts demonstrated elevated antiaging superoxide dismutase (SOD)-like activity (99%). Anti-gout xanthin oxidase inhibitory activity of S. dispora JTS19-1 and V. fragicola SW-9 was also elevated at 79 and 80%, respectively.

• Journal of Food Hygiene and Safety
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• v.3 no.3
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• pp.117-129
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• 1988

Packaged meal manufacturing establishments in Seoul city and Kyungkido province were assessed in terms of the sanitary conditions and practices, time and temperature, and microbiological quality. Sanitary check-lists were developed to evaluate the sanitary condition of sampled packaged meal manufacturing establishments. Microbiological tests on.food containers, equipments, and foods in various phases of product flow were done. The results of the study are summarized as follows; 1) Sanitary condition of kitchen.and sanitary practices of employees in.large and medium establishments were evaluated as the some improvement required in order to meet all standards. But sanitary practices of employees in small establishments were evaluated as the unsatisfactory state with negligence or ignorance of safe practice. 2) The microbiological quality of basic ingredients and food materials after pre-preparation were poor. 3) Time and temperature data indicated that phases of holding ingredients at room temperature after cooking, assembly and packaging before delivery were critical. 4) Microbiological test results for food containers, equipments indicated that sanitary conditions of stainless steel ware, knife, wiping clothes and cutting board should be improved promptly. 5) Critical control points identified were ingredients, pre-preparation, Holding, and assembly and packaging. 6) Guidelines were suggested for effective quality control of packaged meals production.

• Korean Journal of Microbiology
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• v.44 no.1
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• pp.37-42
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• 2008

Optimal conditions for the biodegradation of endocrine-disrupting bisphenol A (BPA) were examined for the white rot fungus Trametes versicolor isolated in Korea. T. versicolor degraded 100% of 50 mg/L bisphenol A during 12 hr in yeast extract-malt extract-glucose (YMG) medium. When BPA was added to the 5-day preincubated fungal culture in YMG medium, all BPA was removed in 2 hr. T. versicolor could efficiently degrade BPA at $35^{\circ}C$, pH 6 in YMG medium. T. versicolor could more easily remove BPA of $1{\sim}25\;mg/L$ than that of higher concentrations ($50{\sim}100\;mg/L$) in YMG medium. T. versicolor degraded 100% of 50 mg/L BPA for 36 h in a minimal medium, which is lower degradation rate than that in YMG medium. Optimal conditions for BPA biodegradation in the minimal medium were similar to those in YMG medium. When BPA (50 mg/L) was added into domestic wastewater, it could be completely removed by T. versicolor. During the biodegradation of BPA by T. versicolor in YMG medium, its estrogenic activity decreased.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.25-31
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• 2016

An enterococci selective medium was developed to detect the presence of enterococci for use as a fecal contamination indicator. Among several media which have been known to detect enterococci, the following 9 different kinds of media were selected: Enterococci Confirmatory agar, Azide dextrose agar, Bromocresol-purple azide agar, Esculin bile agar, Citrate azide tween carbonate agar, KF Streptococcus agar, BROLACIN agar, Kanamycin esculin azide agar, and Membrane filter Enterococcus selective agar. Various components from the nine media were mixed to develop a more effective enterococcus selective medium. The newly developed medium named as 'Enterococcus Mixed medium' was more effective than the previous 9 media. Enterococci strains (Enterococcus avium KACC 10788, Enterococcus faecium KACC 11954, Enterococcus saccharolyticus KACC 10783, Enterococcus durans KACC 10787, Enterococcus faecalis KACC 11304, and Enterococcus hirae KACC 10779) and non-enterococci strains (Escherichia coli KACC 10005, Staphylococcus aureus subsp. aureus KACC 10768, and Bacillus subtilis KACC 10111) were used to test the new medium. As a result, the enterococci strains grew well on the Enterococcus Mixed medium whereas the non-enterococci strains did not grow well on it. Additionally, growth of enterococci with freshwater and seawater samples was observed to be good on the Enterococcus Mixed medium. The result of this study confirmed that the Enterococcus Mixed medium was effective in detecting the target enterococci.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.160-166
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• 2004

The optimal conditions for production of Monascus sp. KM100l cell mass on submerged culture and production of monacolin K on rice solid culture were investigated. An overproducing mutant of Monascus pigments, KM 1001 mutant, from Monascus purpureus KCCM60016 was selected by NTG treatment. The optimal medium for the production of KM100l mutant cell mass is instructed to be composed of 3% glucose, 2% yeast extract, 0.1 % KH$_2$PO$_4$, 0.05% The optimal conditions for production of Monascus sp. KM100l cell mass on submerged culture and production of monacolin K on rice solid culture were investigated. An overproducing mutant of Monascus pigments, KM 1001 mutant, from Monascus purpureus KCCM60016 was selected by NTG treatment. The optimal medium for the production of KM100l mutant cell mass is instructed to be composed of 3% glucose, 2% yeast extract, 0.1 % KH$_2$The optimal conditions for production of Monascus sp. KM100l cell mass on submerged culture and production of monacolin K on rice solid culture were investigated. An overproducing mutant of Monascus pigments, KM 1001 mutant, from Monascus purpureus KCCM60016 was selected by NTG treatment. The optimal medium for the production of KM100l mutant cell mass is instructed to be composed of 3% glucose, 2% yeast extract, 0.1 % $(KH_2PO_4$, 0.05% $MgSO_4{\cdot}7H_2O$, 0.2% L-asparagine, pH 4.5, and the optimal inoculum size and shaking speed were $1.5{\times}10^6$ spores/50 m1 medium and 150 rpm, respectively. On optimal conditions, 4.1 g/l of the cell mass was obtained at 28$^{\circ}C$ for 3 days. The mycelium were inoculated on 500 g of steamed rice using vinyl bag ($30.6{\times}44$ cm) and incubated at $30^{\circ}C$, 85% humidity for 21 days. Lactone form monacolin K was rapidly increased for 2 days and reached highest concentration of monacolin K (2,930 mg/kg) for 15 days, and monacolin K was decreased after 15 days.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.293-298
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• 2002

In order to investigate the ecological aspect of bacteria on groundwater, water samples were collected from various regions. Total of 318 strains were isolated from diluted nutrient broth (DNB) agar medium, and investigated their growth pattern on nutrient broth (NB) medium. As a result, all the isolated strains were divided into two groups, NB and DNB organisms. Growth of DNB organisms were suppressed in full strength NB medium but not in DNB medium, which were called oligotrophic bacteria in this study. Proportion of DNB organisms occurred in the frequency of 50-98% in potable groundwaters (CW, CJ, DPG, CJG1), however, it was 23,46% in polluted site (TJ, NPG1). One hundred and two strains were identified as oligotrophic bacteria and their phylogenetic characteristics were determined by using 16S rDNA sequencing. Based on the phylogenetic analysis, they were found to fall into three major phylogenetic groups: belonging to the Proteobacteria $\alpha$-(49 strains), $\beta$-(50 strains), $\gamma$ -(3 strains) subdivisions. The phylogenetic analysis suggested that microbial diversity of potable groundwater is more complex than that obtained in the past investigation.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.185-192
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• 2009

Chungkookjang fermenting Bacillus subtilis 028-1 strain suppressed the growth of Staphylococcus sp. LS2, Saccharomyces cerevisiae, and Candida albicans. B. subtilis 028-1 strain produced antibiotic effectively in the medium of 2% soybean meal and 1% maltose as a disaccharide, when the shaking was continued 15~18 h and the pH of culture medium was maintained under 6.5. The antibiotic activity was optimized when the initial pH of the culture medium of test strain was adjusted with weak alkali, was remained after 20 min of boiling and for more than 1 month in room temperature, and was weakened slowly by the digestion of chymotrypsin and papain. The molecular weight of the antibiotic was identified between 500 and 1,000 dalton by dialysis, and antibiotic substance was considered as not surfactin but a member of iturin family because of the absence of fibrinolytic activity.