• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.817-822
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• 1998

The authors found out that Aspergillus oryzae ATCC 22787 has the activity to produce a pretty strong chitosanase. Therefore, the strain was used for preparing the chitosan hydrolysate with high antimicrobial activity. The antimicrobial activity of the chitosan hydrolysate was increased gradually with decreasing of viscosity of the solution. The chitosan hydrolysate showing viscosity $5{\sim}10{\;}cp{\;}(30^{\circ}C)$ of 2% solution was revealed the most strong antimicrobial activity. The growth of the Bacillus sp. isolated from the fish meat paste was inhibited with the concentration of 50 ppm. The astringent taste of chitosan solution was reduced with decreasing of viscosity of the solution. The fish meat paste products containing 0.3% chitosan hydrolysate was extended its shelf life by 6 days stored at $15^{\circ}C$, 4 days at $20^{\circ}C$ and 2 days at $30^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.472-479
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• 2002

The antimicrobial effects of metabolites from isolated strains from feces of Korean newborn baby and from Dongchimi against six food-borne microorganisms, and characteristics of the metabolites were investigated.. The metabolites from isolated strains adjusted pH to 3.5, 4.0, and 4.5 showed strong growth inhibition against S. Typhimurium, and S. Enteritidis. The metabolites has kept its inhibition activities to the pathogens after catalase, trypsin or pepsin treatment. In addition, antimicrobial activity of metabolites was not decreased by heat treatment at $121^{\circ}C$ for 15 min. D2 and F35-2 strains were confirmed homofermentative and F20-3 was heterofermentative bacteria identified by final organic acid and gas production. The amount of lactic acid produced by D2 and F35-2 strains after 24 h of incubation was 1.84 and 1.85% respectively, but F20-3 strain produced acetic acid (0.22%) and lactic acid (0.91%).

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.9
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• pp.1106-1112
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• 2007

The solvent extracts of Euphorbia helioscopia, which were extracted by using several solvents with different polarities, were prepared for utility as natural preservatives. The E. helioscopia extract by 80% ethanol was sequentially fractionated with n-hexane, dichloromethane, ethylacetate, and butanol. In order to effectively screen for a natural preservatives agent, we first investigated the antioxidant activities such as DPPH radical scavenging capacity, superoxide radical scavenging capacity, and xanthine oxidase inhibitory activity of the E. helioscopia extracts. By the screening system, we found that ethylacetate fraction had the strongest antioxidant activity in a dose-dependent manner. The antimicrobial activities and cell growth inhibition were investigated for each strain with the different concentrations of E. helioscopia extracts. Antimicrobial activities were shown in ethylacetate fraction of E. helioscopia; however, ethanol, butanol and water fractions showed weak antimicrobial activity against the tested microorganisms. Among the five fractions, ethylacetate fraction showed the highest antimicrobial activities against microorganisms tested, such as Bacillus sublitis, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella Enteritidis and Salmonella Typhimurium. The polyphenol content from ethanol, n-hexane, dichloromethane, ethylacetate, butanol, and water fractions were 207.46 mg/g, 45.45 mg/g, 138.23 mg/g, 678.02 mg/g, 278.91 mg/g, and 63.76 mg/g, respectively. There seems to be a close relationship between antioxidant activities, and antimicrobial activities and polyphenol content in natural plant. From these results, it is suggested that E. helioscopia could be used for the ethylacetate fraction and could be suitable for the development of a food preservative.

• Research in Plant Disease
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• v.26 no.4
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• pp.210-221
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• 2020

This research was executed to select beneficial antagonists from digestive organ of Allomyrina dichotoma larva that can be put on environment friendly control against phytopathogenic fungi. We screened 38 bacterial strains inhibiting mycelial growth against eight plant pathogens through dual culture assay. The 10 strains among 38 bacterial strains were selected as beneficial microbes showing antifungal activity against Botrytis cinerea, Plasmodiophora brassicae, Colletotrichum acutatum and Phytophthora capsici through under greenhouse pot trials. The 10 bacterial strains that shown strongest antifungal activity were classified into 3 genera and 10 species, and identified as the genus Bacillus (DM146, DM152, DH2, and DH16), Paenibacillus (DF30, DH14, and DM142) and Streptomyces (DF137, DM48, and DH92) by morphological characteristics and 16s rRNA gene sequence. The 10 bacterial strains had solubilizing activity of insoluble phosphates, production of IAA (indole-3-acetic acid), β-1,3-glucanase and protease. Among the 10 bacterial strains, DM152 strain was produced significant enhancement of all growth parameters of chili pepper and tomato seedlings under greenhouse condition. Thus, this study demonstrated that gut microbes of Allomyrina dichotoma larva will be useful as a potential biocontrol agent against plant pathogens and biofertilizer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.3
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• pp.320-326
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• 2012

This study was conducted to investigate the antibacterial and antioxidative activities of water and ethanol extracts from a mixture of roasted coffee and red ginseng. The antibacterial effects of each extract were determined by the classical paper disc method. A water extract of mixture samples inhibited growth of all strains, but antibacterial effects were mostly weakened. Ethanol extracts showed stronger antibacterial effects than water extracts in all strains except Gram negative Escherichia coli and the fungi strain Candida albicans. Also, the antibacterial effect of the Bacillus cereus strain appeared in all samples, and the ES2 sample formed a clear zone of 19 and 20 mm against Pseudomonas aeruginosa and S. Typhimurium respectively (MIC=0.25 and 0.125 mg/mL). Determinations of free radical elimination for the different mixture extracts using 1,1-diphenyl-2-picrylhydrazyl (DPPH) were compared with ascorbic acid and butylated hyderoxytoluene as positive controls. The water and ethanol extracts of mixture samples (100 ${\mu}g/mL$) showed 55.38~60.01% and 59.37~70.50% DPPH scavenging activities, respectively. DPPH scavenging activities of all mixture samples were slightly higher than roasted coffee and red ginseng samples. However, DPPH scavenging activity decreased when red ginseng extract composed more than 70% of the total extract. The total polyphenol in the mixture samples measured by the Folin-Denis method revealed the highest level of polyphenol content in ethanol extract of sample 3, whereas polyphenol content differed with different mixture ratios, ranging from 105.16~119.79 mg/g in ethanol extract. In the water extract, the polyphenol content was greatest with water extract of sample 1, whereas in other samples the content varied from 93.75~109.18 mg/g.

• Journal of Life Science
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• v.33 no.11
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• pp.915-922
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• 2023

Lactic acid bacteria (LAB) are widespread in a variety of environments including fermented dairy products, gastroinstetinal and urogenital tracts of human and animals, plant, soil and water. Leuconostoc mesenteroides DB3 was detected by the strongest antibacterial activities among 24 Leuconostoc strains isolated from Camellia japonica flowers. Acid tolerance of L. mesenteroides DB3 existed up to pH 2.5, but the resistance did not show at pH 2.0, which relatively excellent acid resistance existed. Bile acid tolerance was very stable within the test range to 1.2%. L. mesenteroides DB3 exhibited the optimal growth at 30℃, and showed a slight slow growth when compared with L. mesenteroides KCTC3505, which reached a stationary phase at 18 hr. The pH was changed along with the growth curve, but was maintained above pH 3.98. L. mesenteroides DB3 had higher initial antibacterial activities when compared to L. mesenteroides KCTC3505, but it showed similar activities with the standard strain after the latter part of the logarithmic growth phase. Although lactic acid production in L. mesenteroides DB3 was induced by lower amount in the initial part to the standard strain, it was exhibited by similar amounts after the late logarithmic growth phase. Muicin adhesion of L. mesenteroides DB-3 maintained superior to L. mesenteroides KCTC3505. Both strains showed excellent emulsification ability for kerosene. In summary, we evaluate that L. mesenteroides DB-3 has a high potential for application as probiotics owing to its excellent antibacterial activity, acid resistance, bile acid resistance, and muicin adhesion.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.902-907
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• 2000

Protamine-strong basic protein was prepared from salmon(chum salmon, Oncorhynchus keta) sperm by several pretreatment method. And there were determined yield, amino acid composition, antimicrobial and antioxidant activity of protamine on each pretreatment condition. The yield of protamine was different according to pretreatment, and ultrasonicating, homogenizing and microwaving pretreatment were about 16.0%, 15.5% and 10%, respectively. The main amino acid of P60(microwaving pretreatment for 10 min at $80^{\circ}C$) and UU6(ultrasonicating pretreatment for 60 min at $20^{\circ}C$) were arginine, proline and tryptophan, and arginine content of P60 and UU6 were 61%, 53%, respectively. On the other hand, main amino acid of M(homogenizing pretreatment by mixer) were methionine, proline and arginine, the content were 34%, 28% and 11%, respectively. Also MC(homogenizing pretreatment with $H_{2}SO_{4}$ soln. by mixer) was very different with P60, UU6 and M, the content of MC were proline 44.8% and arginine 39.7%. Prepared protamines showed antimicrobial activity to several gram(+) and gram(-) strain. In particular, the UU6 and P60 protamine has strong antimicrobial activity to Bacillus subtilis and Escherichia coli, and the activity was increased with concentration increasing. Regardless of pretreatment method, all protamine showed antioxidant activity and the $EDA_{50}$ of P60, UU6, M and MC were $101\;{\mu}g/mL$, $410\;{\mu}g/mL$, $523\;{\mu}g/mL$ and $490\;{\mu}g/mL$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.10
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• pp.1690-1700
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• 2013

The objective of this study is to develop and validate predictive growth models for Bacillus cereus (diarrhea type) vegetative cells, spores and Staphylococcus aureus in preprocessed Namul (bracken and Chwinamul) and root vegetables (bellflower and burdock). For validation of model performance, growth data for S. aureus in preprocessed vegetables were collected at independent temperatures (18 and $30^{\circ}C$) not used in the model development. In addition, model performance of B. cereus (diarrhea type) in preprocessed vegetables was validated with an emetic type of B. cereus strain. In primary models, the specific growth rate (SGR) of the B. cereus spores was faster than that of the B. cereus vegetative cells, regardless of the kinds of vegetables at 24 and $35^{\circ}C$, while lag time (LT) of the B. cereus spores was longer than that of the B. cereus vegetative cells, except for burdock. The growth of B. cereus and S. aureus was not observed in bracken at temperatures lower than 13 and $8^{\circ}C$, respectively. The LT models for B. cereus (diarrhea type) in this study were suitable in predicting the growth of B. cereus (emetic type) on burdock and Chwinamul. On the other hand, SGR models for B. cereus (diarrhea type) were suitable for predicting the growth of B. cereus (emetic type) on all preprocessed vegetables. The developed models can be used to predict the risk of B. cereus and S. aureus in preprocessed Namul and root vegetables at the retail markets.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.304-313
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• 2016

One of the issues currently facing nuclear power plants is how to store spent nuclear waste materials which are contaminated with radionuclides such as $^{134}Cs$, $^{135}Cs$, and $^{137}Cs$. Bioremediation processes may offer a potent method of cleaning up radioactive cesium. However, there have only been limited reports on $Cs^+$ tolerant bacteria. In this study, we report the isolation and identification of $Cs^+$ tolerant bacteria in environmental soil and sediment. The resistant $Cs^+$ isolates were screened from enrichment cultures in R2A medium supplemented with 100 mM CsCl for 72 h, followed by microbial community analysis based on sequencing analysis from 16S rRNA gene clone libraries(NCBI's BlastN). The dominant Bacillus anthracis Roh-1 and B. cereus Roh-2 were successfully isolated from the cesium enrichment culture. Importantly, B. cereus Roh-2 is resistant to 30% more $Cs^+$ than is B. anthracis Roh-1 when treated with 50 mM CsCl. Growth experiments clearly demonstrated that the isolate had a higher tolerance to $Cs^+$. In addition, we investigated the adsorption of $0.2mg\;L^{-1}$ $Cs^+$ using B. anthracis Roh-1. The maximum $Cs^+$ biosorption capacity of B. anthracis Roh-1 was $2.01mg\;g^{-1}$ at pH 10. Thus, we show that $Cs^+$ tolerant bacterial isolates could be used for bioremediation of contaminated environments.