• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1276-1284
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• 2018

probiotics strains promoting the health are a collection of microorganisms that improve or restore microbial populations in the intestines. In this study, Leuconostoc probiotics was isolated from fermented gimchi and identified. Angelica dahurica, containing abundantly antioxidant activity, imperator, is a wildly grown species of angelica native. Before fermentation, total phenolics compound were $48.83{\pm}4.9GAE\;mg/g$ in the Angelica dahurica extract. After fermentation total phenolic compounds were $97.7{\pm}12.6GAE\;mg/g$. The total amount of phenol in the fermented product was 30.2% higher than that before fermentation. The total flavonoid content before fermentation was $9.86{\pm}4.3mg/g$ and the total flavonoid content was $37.17{\pm}7.4mg/g$ after fermentation, which was 82.3% higher than before fermentation. The DPPH radical scavenging activity, superoxide radical scavenging activity, hydroxy radical scavenging activity and $Fe^{{+}{+}}$ chelating antioxidative activity of the Angelica dahurica extract were $41.6{\pm}7.1%$, $65.7{\pm}8.4%$, $55.26{\pm}9.4%$ and $17.5{\pm}4.6%$, respectively. After fermentation, they were $60.3{\pm}12.6%$, $78.8{\pm}8.3%$, $56.9{\pm}4.9%$ and $36.6{\pm}8.9%$, respectively. Therefore, the present study suggests that the fermentation using the probiotics strain of the Angelica dahurica extract can be used as a functional health food and cosmetic material with increased antioxidant capacity.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.163-170
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• 2012

In order to inhibit the growth of pathogens and degrade biogenic amines during the fermentation of soybean products, an isolate with antimicrobial activity against pathogens and biogenic amine-degrading property was obtained from 83 traditionally fermented soybean products. The morphological and biochemical tests and the phylogenetic relationship among 16S rRNA gene sequences indicated that the isolate named as the strain SCK B11 was most closely related to Bacillus licheniformis. The cell-free supernatant of two day cultures was active against several pathogens including Enterococcus faecalis, Listeria monocytosis, Micrococcus luteus, Pseudomonas aeruginosa, Bacillus cereus, and Staphylococcus aureus. PCR analysis was conducted to determine relatedness to antimicrobial lantibiotics and biosurfactants produced by Bacillus spp., but showed negative for the genes encoding surfactin, lichenysin, and lichenicidine. Electron microscopic observation indicated that the antimicrobial agent seemed to attack the membrane of the pathogens, leaving the ghost or shrunken cells. The strain was found to degrade histamine by 72% and tyramine by 66% in the cooked soybean containing 5.3% of biogenic amine over 10 days of fermentation time. The use of selected strain would be a potential control measure in manufacturing traditionally fermented soybean products that are difficult to control pathogens and biogenic amine levels.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.169-176
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• 2015

The malolactic fermentation (MLF), which is widely used in winemaking, is the conversion of malic acid to lactic acid conducted by the malolactic enzyme (Mle) of lactic acid bacteria. In order to select the strains with MLF among 54 lactic acid bacteria isolated from the traditionally fermented foods, we designed a primer set that specifically targets the conserved regions of the mle gene and then selected four strains that harbor the mle gene of Lactobacillus plantarum. All strains were identified as L. plantarum by analyzing the 16S rRNA sequences, biochemical properties, and the PCR products of the recA gene. From comparison of the mle gene sequences consisting of 1,644 bp, the nucleotide and amino acid sequence of strain JBE60 correspond to 96.7% and 99.5% with those of other three strains, respectively. The strain JBE60 showed the highest resistant against 10% (v/v) ethanol among the strains. The strains lowered the concentration of malic acid to average 43%. Considering the ethanol resistance and conversion of malic acid, the strain JBE60 is considered as a potential starter for the malolactic fermentation.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.761-767
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• 2022

EHT1 and EEB1 are the key Saccharomyces cerevisiae genes involved in the synthesis of ethyl esters during wine fermentation. We constructed single (Δeht1, Δeeb1) and double (Δeht1Δeeb1) heterogenous mutant strains of the industrial diploid wine yeast EC1118 by disrupting one allele of EHT1 and/or EEB1. In addition, the aromatic profile of wine produced during fermentation of simulated grape juice by these mutant strains was also analyzed. The expression levels of EHT1 and/or EEB1 in the relevant mutants were less than 50% of the wild-type strain when grown in YPD medium and simulated grape juice medium. Compared to the wild-type strain, all mutants produced lower amounts of ethyl esters in the fermented grape juice and also resulted in distinct ethyl ester profiles. ATF2, a gene involved in acetate ester synthesis, was expressed at higher levels in the EEB1 downregulation mutants compared to the wild-type and Δeht1 strains during fermentation, which was consistent with the content of acetate esters. In addition, the production of higher alcohols was also markedly affected by the decrease in EEB1 levels. Compared to EHT1, EEB1 downregulation had a greater impact on the production of acetate esters and higher alcohols, suggesting that controlling EEB1 expression could be an effective means to regulate the content of these aromatic metabolites in wine. Taken together, the synthesis of ethyl esters can be decreased by deleting one allele of EHT1 and EEB1 in the diploid EC1118 strain, which may modify the ester profile of wine more subtly compared to the complete deletion of target genes.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.323-328
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• 2010

After supplemention with the licorice (Glycyrrhiza glabra), mustard (Brassica juncea), and chitosan as food additives to low-salted doenjang containing 30% lower salt than control doenjang (12.7% salt), fermentation properties of doenjang were investigated for 40 days. Adding the licorice, mustard, and chitosan to low-salted doenjangs containing 10.2% and 8.9% of salt did not affect the acidity, viable cell count, or color of doenjang. A white pellicle-forming strain was detected at the surface of low-salted doenjangs (10.2% and 8.9% salt) but not the control doenjang and low-salted doenjangs added with mixed additives (licorice, mustard, and chitosan). The amino nitrogen content of 8.9% salted doenjang added with mixed additives at 20 days was 332 mg% and this value was similar to that of 12.7% salted doenjang at 40 days. In sensory evaluation, the 8.9% salted doenjang added the additives had the highest score in overall palatability. These results indicate that salt contents of doenjang could be lowered to 8.9% by adding licorice, mustard, and chitosan, resulting in improved palatability, shortened fermentation period, and inhibited abnormal fermentation.

• The Korean Journal of Mycology
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• v.46 no.3
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• pp.307-314
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• 2018

The goal of this study was to investigate the microbiological characteristics of the ethanol-producing wild yeast, Aureobasidium pullulans P-1, isolated from flowers growing near the Yedang reservoir, Chungnam province, Korea, and in addition, to optimize its fermentation ability for the production of Makgeolli. A. pullulans P-1 was oval-shaped, and formed ascospores and pseudomycelium. The P-1 strain was a halophilic and sugar tolerant yeast which grew in 15% NaCl and 50% glucose-containing yeast extract-peptone-dextrose media. The P-1 strain was also resistant to 20% ethanol. Changes of the physicochemical properties during Makgeolli fermentation by A. pullulans P-1 were investigated. A maximum of 8.45% ethanol was obtained when a mixture of cooked rice, 150% water, and 35% ipguk per cooked rice was fermented by 5% A. pullulans P-1 culture broth at $25^{\circ}C$ for 10 days. Antihypertensive angiotensin I-converting enzyme inhibitory activity in the Makgeolli ferment produced by A. pullulans P-1 reached a high of 71.1% after 10 days.

• Herbal Formula Science
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• v.17 no.1
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• pp.121-128
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• 2009

Gyoungok-go (GOG; Qiongyu-gao in Chinese) has been used in traditional oriental medicine for the improvement of various physiological vitality functions. The aim of present work is to investigate a processing possibility of vinegar using GOG. GOG vinegar was prepared by two stage fermentations of alcohol and vinegar. The method of GOG fermentation with polished rice as a fermentation substrate is not yet established. The result of alcohol fermentation rate of GOG with some strains, strain No. 1 produced the highest alcohol contents among 7 strains. The strain No. 1 identified Saccharomyces paradoxus by 18S rDNA classification. S. paradoxus was produced over 20% alcohol in the 1$\sim$11% GOG with polished rice. A. aceti was produced 8.52% acetic acid from 6.5% alcohol containing 11% GOG, after incubation for 11 days.

• The Korean Journal of Mycology
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• v.42 no.4
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• pp.333-340
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• 2014

The aim of this study was to isolate a potential multifunctional biocontrol agent from bacteria for control of multiple plant diseases as an alternative to fungicides. A total of 201 strains were isolated from soil undamaged by repeated cultivation in Sunchang and their ability to produce antibiotics, siderophores and extracellular enzymes such as protease, cellulase and amylase was investigated. Selected strain SCS3 produced cellulose, protease and amylase. This strain also produced siderophores and showed excellent antifungal activity against various phytopathogens. SCS3 was identified as Bacillus subtilis using 16S rRNA sequencing, and named Bacillus subtilis SCS3. Finally, physiological and biochemical characteristics of B. subtilis SCS3 were examined. From the results, B. subtilis SCS3 was found to be a useful multifunctional biocontrol agent against various phytopathogens.

• The Korean Journal of Food And Nutrition
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• v.37 no.4
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• pp.189-196
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• 2024

To develop farm-made high effective vinegar, this study prepared apple vinegar using four kinds of acetic acid bacteria isolated from a natural fermentation liquid of 'Cheongsoo' grapes and analyzed vinegar samples fermented 93% apple juice and 7% alcohols at 30℃ for 20 days. To accomplish this, quality characteristics such as pH, total acidity, reducing sugar, organic acid, color, total polyphenol contents, and antioxidant activity contents were determined. The pH decreased while total acidity of all samples gradually increased during fermentation period. The vinegar with AP 21 strain tended to increase the total acidity quicker than other stains. Reduced sugar content remained high until the last fermentation day. Furthermore, reduced sugar contents of all vinegars increased as fermentation progressed by decomposing sucrose present in apples. When physiological activities were compared, apple vinegars fermented with AP 21 and 30 strains had higher total polyphenol and flavonoid contents than other samples. However, there was no significant difference in antioxidant activity between samples. These results indicate that strain 21 is the most suitable starter as acetic acid bacteria for producing farm-made vinegar.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.85-90
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• 1992

Rice bran was employed as a main medium component for ethanol fermentation by Saccharomyces species. Among the several strains of .Saccharomyces yeasts. S. cerevisiae IF0 2346 was selected as the hest strain in view of the interest in the production of ethanol and amino acids. It was found that S. cerevisiae IF0 2346 showed $3\times 10^8$cells/d and 4.7% (v/v) ethanol production after 72 hr cultivation. Although total amount of free amino acids was decreased from 1.099 mg/l to 829 mg/l during the fermentation, glutamic acid. histidine, and isoleucine were increased considerably. With the supplement of 5% glucose to the ferrnentation medium, both ethanol and amino acid production were increased up to 134% and 264%, respectively. compared to the control case. Glutamic. acid, leucine, alanine. phenylalanint:, and valine were the major amino acids in the fermentation broth.