• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.3
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• pp.184-190
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• 1984

Sardine, Sardinops melanosticta, has been caught more than fifty thousand metric tons every year in adjacent sea of Korea, but most of them used for uneatable fish meal because of their rapid spoilage. Usually it is known that the main reason of putrefaction of foods is caused by the maicro-organisms included in them. Therefore, this experiment was carried out to identify the micro-organisms isolated from the intestine of fresh sardine and characterize their proteolytic enzymes produced from them. Aerobic cell count ranged from $1.7{\times}10^4\;to\;3.6{\times}10^5/g$, while anaerobic cell count, from $2.9{\times}10^4\;to\;5.5{\times}10^5/g$. Most of the isolated strains were psychrotrophic mesophiles. Among the two hundred and eighty strains isolated from the fresh samples, fifty-six strains ($20.0\%$) were proteolytics, one hundred and seventy-five strains ($62.5\%$) were lipolytics and tenty-nine strains ($10.5\%$) had the ability to produce hydrogn sulfide. The most predominantly isolated microbial groups from the fresh sardine were Moraxella ($31.4\%$) and Pseudomonas sup. ($28.6\%$). Flavobacterium-Cytophaga, Vibrio, Acinetobacter, Micrococcus spp. and Enterobacteriaceae appeared from $7.9\%\;to\;5\%$ out of total tested strains. The average bacterial count in the spoiled samples (stored at about $18^{\circ}C$ for 48 hours) was increased to the level of $2.9{\times}10^8/g$ for aerobes, $1.5{\times}10^8/g$ for anaerobes, then one hundred and ten strains, corresponding to $52\%$, out of two hundred and thirteen strains submitted to the test were proteolytics. The strongest proteolytic bacterium among the two hundred and eighty strains was identified as Pseudomonas 101 which grew best at $25^{\circ}C$. The optimum condition for the activity of the proteolytic enzyme produced by Pseudomonas 101 appeared $35^{\circ}C$ and pH 9.0, but the activity was relatively unchanged between 5.0 and 11.0 of pH and between $30^{\circ}C\;and\;50^{\circ}C$ of temperature.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.592-599
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• 2012

The effect of additives on the quality of low-salt doenjang was investigated. The amylase activity of the mustard added group decreased during the fermentation period, and the number of yeast and bacteria was also decreased during the fermentation period. The oxidation-reduction potential was low at the later fermentation stages for the mustard and mustard-garlic added groups, and water activity decreased considerably for the alcohol added group. The L-value of alcohol added doenjang decreased with increases in the a-value. The pH was 4.84 in the mustard added group. The reducing sugar content was 10.15% in the alcohol-garlic added group, and the alcohol production was limited by adding mustard. The amino-type and ammonia-type nitrogen were high in garlic and mustard added groups. Alcohol and alcoholgarlic added groups exhibited significantly improved taste and overall acceptability of doenjang.

• Journal of Life Science
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• v.29 no.11
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• pp.1173-1178
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• 2019

The purpose of this study was to isolate an agar-degrading marine bacterium and characterize its agarase. Bacterium BK-1, from Gwanganri Beach at Busan, Korea, was isolated on Marine 2216 agar medium and identified as Agarivorans sp. BK-1 by 16S rRNA gene sequencing. The extracellular agarase, characterized after dialysis of culture broth, showed maximum activity at pH 6.0 and $50^{\circ}C$ in 20 mM Tris-HCl buffer. Relative activities at 20, 30, 40, 50, 60, and $70^{\circ}C$ were 67, 93, 97, 100, 58, and 52%, respectively. Relative activities at pH 5, 6, 7, and 8 were 59, 100, 95, and 91%, respectively. More than 90% of the activity remained after a 2 hr exposure to 20, 30, or $40^{\circ}C$; about 60% of the activity remained after a 2 hr exposure to $50^{\circ}C$. Almost all activity was lost after exposure to 60 or $70^{\circ}C$ for 30 min. Zymography revealed three agarases with molecular weights of 110, 90, and 55 kDa. Agarose was degraded to neoagarobiose (46.8%), neoagarotetraose (39.7%), and neoagarohexaose (13.5%), confirming the agarase of Agarivorans sp. BK-1 as a ${\beta}$-agarase. The neoagarooligosaccharides generated by this agarase could be used for moisturizing, bacterial growth inhibition, skin whitening, food treatments, cosmetics, and delaying starch degradation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.21 no.2
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• pp.112-128
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• 1995

This study was undertaken to see the effect of the addition of residential sewage to cosmetic plant wastewater on the aeration time for COD stabilization of the mixture in a bioreactor. Various range of mixing-ratio samples were tested to find the optimal mixing ratio. The combined result of measured COD and the minimum aeration time was desirable when the sewage portion was 80%. It was found that the addition of residential sewage to cosmetic plant wastewater itself reduced the measured COD of the mixture without any further treatment. And during the aeration COD was reduced with increasing the portion of the sewage. These results show that the aeration time for COD stabilization can be reduced by pro-mixing of residential sewage and the cosmetic plant wastewater.

• The Korean Journal of Mycology
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• v.41 no.4
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• pp.248-254
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• 2013

A Gram-negative bacterium was isolated from mushroom media that markedly reduces the level of extracellular toxins (i.e., tolaasins) produced by Pseudomonas tolaasii, the most destructive pathogen of cultivated mushrooms. The HC1 strain was selected as detoxifying tolaasin by bioassay on potato and it was identified Pseudomonas sp. by the cultural, morphological and physiological characteristics, and analysis of the 16S rRNA. The isolated bacterium is saprophytic but not parasitic nor pathogenic to cultivation mushroom. The isolated bacterium for P. tolaasii cell, was sufficient for detoxification in vitro. Inoculation of the isolated bacterium prevents the development of bacterial disease in Pleurotus ostreatus, Flammunia velutipes and Agaricus bisporus. Control efficacy of brown blotch of strain HC1 treatment was 69, 68 and 55% on Agaricus bisporus, Flammulina velutipes and Pleurotus ostreatus, respectively. The suppressive bacterium may be useful in future for the development of biocontrol system and the construction of genetically modified edible fungi resistant to the disease caused by P. tolaasii.

• Journal of the Korean Chemical Society
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• v.40 no.1
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• pp.72-80
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• 1996

A chitinase-producing bacterium, Serratia marcescens JM, was isolated from a seashore muds. A chitinase was purified by ammonium sulfate precipitation, affinity adsorption, hydroxylapatite and sephadex G-200 column chromatography. The chitinase obtained from Serratia marcescens JM was purified 42.2 folds with the overall yield of 7.1%. The purified chitinase showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular weight of the enzyme was 59,000 and the apparent kinetic parameters $K_m\;and\;V_{max}$ for the purified chitinase were 5.17 mg/mL and 39.8 unit/mL, respectively. The optimum pH and temperature of the purified chitinase were 7.0 and 50$^{\circ}C$, respectively and the purified enzyme was stable on pH 7.0 up to 50$^{\circ}C$. The enzyme were activated by $Cu^{2+},\;Ca^{2+}\;and\;Mg^{2+}$ and inhibited by $Hg^{2+}$ respectively. In addition, Cysteine increased the chitinase activity and EDTA, MIA, PCMB and SDS inhibited enzyme activities. Major cations, $MG^{2+},\;Ca^{2+},\;K^+\;and\; Na^+$ present in seawater slightly stimulated the chitinase activity.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.16-21
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• 2004

Six bacterial strains which formed large halo on chitosan-containing agar plate were isolated from beach mud and crabs at South coast of Korean peninsula. They were designated as Bacillus cereus KNUC51, B. cereus KNUC52, B. cereus KNUC53, B. cereus KNUC54, B. cereus KNUC55, and Paenibacillus favisporus KNUC56 by analysing their morphologies and 16S rDNA sequences. Chitosanase activities of all isolates were similar to that of B. subtilis 168. To enhance the activity of chitosanase, a powerful mutagen, MNNG was treated for P favisporus KNUC56. Three mutants showed higher activity of chitosanase than that of the original strain. The DNA fragments containing chitosanase gene from B. cereus sources were cloned, sequenced, and their deduced amino acid sequence analysis showed over 93% homologies with that of the known B. cereus ATCC14579. Extracellular sample from the isolates was incubated in proper reaction mixture including chitosan for 5 minutes at $37^{\circ}C$ to produce 3-10 chitosan oligomers which has been known to be active for clinical agents and agronomical agents.

• KSBB Journal
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• v.14 no.1
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• pp.96-102
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• 1999

Marine bacterium Bacillus cereus ASK202 produced an extracellular agarase (E.C.3.2.1.81) which showed a high level of enzyme activity in the presence of agar and agarose. In the optimal culture conditions, the agarase production increased 7.7 folds compared with the one obtained from the basal medium. Agarase production reached upto 160 units/L after 24hr of cultivation in a modified marine medium at $25^{\circ}C$. The degree of purification increased 31.5 folds with 27.8% yield through freeze drying, DEAE Sepharose CL-6B and Superose 6HR 10/30 column chromatography. The molecular weight of the purified agarase was determined to be 90,000 daltons by gel-permeation filteration. Optimal temperature and pH for the enzyme activity were $40^{\circ}C$ and 7.8, respectively. The enzyme was stable up to $50^{\circ}C$ and at a broad pH range of 5.0-10.0. The $\beta$-agarase was activated by $Zn(NO_3)_2$, and was inhibited by $CuSO_4$ and $SnCl_2$. The Km and Vmax values of this enzyme for agarose as a substrate was $2.4mg/m\ell$ and 13.6 mg/m$\ell$, respectively.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.47-53
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• 2015

Various diseases occur in fruits, leave and roots during strawberry cultivation and cause severe economical damage and huge amount of chemical fungicide use. Recently, as consumers' interest in safety of foods and organic agriculture produces have increased, control measures using alternatives for chemical fungicides have been newly developed in various ways. This study was conducted to test antifungal activity and control effect of sodium dichloroisocyanurate (NaDCC), using as disinfectants, against major disease pathogens of strawberry, Fusarium oxysporum (Fusarium wilt), Colletotrichum gloeosporioides (Anthracnose) and Phytophthora sp. (Phytophthora blight), and Xanthomonas fragariae (bacterial angular leaf spot) and evaluate availability as environment-friendly materials. When NaDCC was treated at the concentration range of 150 to 300 ppm, it suppressed significantly hyphal growth and reduced spore germination by more than 28%. In field condition, NaDCC showed excellent control effect (control value: 50%) against the bacterial angular leaf spot disease. Based on above-described results, we suggested that NaDCC can be used as alternative candidates to chemical pesticide alternatives of for controlling strawberry diseases.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.2
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• pp.90-96
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• 2022

Purpose: The purpose of this study was to investigate antimicrobial activity of extracts from shiitake mushroom against periodontopathogens and its cytotoxicity for human gingival fibroblast. Materials and Methods: Shiitake mushroom was soaked in water and acetone, and the supernatant was dried to collect its extract. The susceptibility of periodontopathogens for the extracts was investigated. Human gingival fibroblast was treated with the extracts, and the cell viability was measured CCK-8 solution. Results: The water extract from shiitake mushroom significantly reduced the growth of periodontopathogens at 2.5 mg/ml (P < 0.05). The acetone extract significantly inhibited the growth of Porphyromonas gingivalis and Tannerella forsythia at 0.32 mg/ml and Treponema denticola growth at 0.64 mg/ml (P < 0.05). The cytotoxicity of the extract was shown at a concentration of 2.5 mg/ml. The extracts with a concentration of 1.25 mg/ml appeared to be reduce cell viability after 4 h. Conclusion: The extracts of shiitake mushroom have antimicrobial activity against periodontitis-causing bacteria and relieving inflammation. Therefore, the extracts may be a candidate for preventing and treating periodontal disease.