• Applied Biological Chemistry
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• v.33 no.4
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• pp.330-336
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• 1990

In order to Process rapid fermented anchovy with low salt contents, processing condition of rapid fermented anchovy by proteolytic bacteria, and its chemical composition and quality stability during storage were examined. Culture was performed(pH 7.0, $40^{\circ}C$, 45strokes/min) for 15hrs after the addition of 1% of NaCl, 1% of sodium erythorbate and 20m1 of B. licheniformis p-5 cultures($3.2{\times}10^4cells/ml$) to 100g of raw anchovy, and then low salt fermented anchovy as final product was made by adding of several(3% of NaCl, 4% of KCI, 4% of ethyl alcohol(w/v), 0.5% of ginger, 0.5% of garlic powder) for stability and flavor enhancement. During 60days of storage, histamine contents was adequate in a food sanitation aspect, and microflora decreased sharply while volatile basic nitrogen increased slowly. Free amino acids are the major part in unique fermented anchovy taste. The volatile fatty acids is the most important component in the anchovy's flavor. From the results of experiments, it was supposed that rapid fermented anchovy processed with proteolytic bacteria was suitable.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.73-79
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• 2010

The Korea Polar Research Institute (KOPRI) has assembled a culture collection of cold-adapted bacterial strains from both the Arctic and Antarctic. To identify excellent protease-producers among the proteolytic bacterial collection (874 strains), 78 strains were selected in advance according to their relative activities and were subsequently re-examined for their extracellular protease activity on $0.1{\times}$ ZoBell plates supplemented with 1% skim milk at various temperatures. This rapid and direct screening method permitted the selection of a small group of 15 cold-adapted bacterial strains, belonging to either the genus Pseudoalteromonas (13 strains) or Flavobacterium (2 strains), that showed proteolytic activities at temperatures ranging between $5-15^{\circ}C$. The cold-active proteases from these strains were classified into four categories (serine protease, aspartic protease, cysteine protease, and metalloprotease) according to the extent of enzymatic inhibition by a class-specific protease inhibitor. Since highly active and/or cold-adapted proteases have the potential for industrial or commercial enzyme development, the protease-producing bacteria selected in this work will be studied as a valuable natural source of new proteases. Our results also highlight the relevance of the Antarctic for the isolation of protease-producing bacteria active at low temperatures.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.5
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• pp.363-369
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• 1989

In this study, the biochemical characterization of strong proteolytic bacteria and their extracellular pretense isolated from fermented fish paste were experimented for the purpose of industrial large scale-production by accelerated fermentation. The results obtained were as follows: Among 4 strains isolated from fermented fish paste, B. subtilis p-4 and B. licheniformis p-5, which grow well at $40^{\circ}C$, pH 7.0 and $1\%$ of salt contents, were the best proteolytic bacteria and were shown $0.48hr^{-1}$, $0.49hr^{-1}$ of specific growth rate in TPY medium, respectively. Maximum enzyme activity of B. subtilis p-4 was 335n mole-Tyr/min.ml after 30 hrs and that of B. licheniformis p-5 was 300n mole-Tyr/min.ml after 28 hrs of shaking culture. Purified pretense produced by B. subtilis p-4 and B. licheniformis p-5 showed maximum activity at $50^{\circ}C$, pH 7.0 and molecular weight were estimated to be 18,000, 30,000 by sephadex G-100 gel filtration, respectively. These were supposed to be a kind of metal chelator sensitive neutral pretense from the result of high sensitivity against EDTA, o-phe-nanthroline and metal ions such as $Cu^{2+},\;Ni^{2+},\;Zn{2+}$.

• Korean Journal of Microbiology
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• v.24 no.3
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• pp.308-316
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• 1986

Vertical distribution of heterotrophic bacteria and physico-chemical characteristics were measuted in Kum River estuarine sediments. And interrelationship between heterotrophic bacterka and environmental factors was also studied. The type of sediment of Site 1 was silty clay, and sand at Site 2. Annual pH ranges were between 7.1 and 7.7 in the clay type sediment (Site 1) and 6.9-7.2 in the sand type sediment (Site 2). It was shown that organic matter contents were higher in the clay type sediment than those of sand type sediment. Redox potential values of sediments were decreased rapidly with depth at Site 1, but those of Sete 2 showed vertical fluctuation. Nitrogens(ammonia+amino acid-N, nitrate-N, nitrite-N) and phosphate in the clay type sediment showed higher values than those of sand type sediment. Annual distribution of heterotrophic bacteria were ranged $6.71{\times}10^4$ cells/g dry wt. $-2.50{\times}10^6$ cells/g dry wt. In the clay type sediment and $2.67{\times}10^3$ cells/g dry wt. $-1.94{\times}10^6$ cells/g dry wt. in the sand type sediment. Distribution of proteolytic, lipolytic, and amylolytic bacteria were decreased with the depth and the highest density was found in April and the lowest in January. Bacterial populations in sediments were closely correlated with such environmental factors as pH, redox potential, moisture content, organic matter contents, and inorganic nutrients such as nitrite-N and phosphate-P.

• Food Science of Animal Resources
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• v.39 no.1
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• pp.73-83
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• 2019

The aim of this study was to investigate the effect of glucose oxidase (GOX) immobilized on magnetic chitosan nanoparticles (MCNP) on the viability of probiotic bacteria and the physico-chemical properties of drinking yogurt. Different concentrations (0, 250, and 500 mg/kg) of free and immobilized GOX were used in probiotic drinking yogurt samples. The samples were stored at $4^{\circ}C$ for 21 d. During storage, reduction of the number of probiotic bacteria in the samples with enzyme was lower than the control sample (without enzyme). The sample containing 500 mg/kg immobilized enzyme had the highest number of Bifidobacterium lactis and Lactobacillus acidophilus. The samples containing immobilized enzyme had lower acidity than other samples. Moreover, moderate proteolytic activity and enough contents of flavor compounds were observed in these samples. It can be concluded that use of immobilized GOX is economically more feasible because of improving the viability of probiotic bacteria and the physico-chemical characteristics of drinking yogurt.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.357-365
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• 1994

The effects of garlic concentrations on the properties of squid sik-hae such as the chemical and microbial changes were investigated. pH, the amounts of lactic acid showed significant differences at early stages of fermentation and no significant differences at later stages with increasing garlic concentrations. The amount of TMAO decreased with increasing storage periods and garlic concentrations, whereas that of TMA increased significantly at early stages of fermentation and showed no significant differences with increasing garlic concentrations. At later stages of fermentation, the amount of TMA at $2\%$ garlic concentration was higher than those at 3 and $4\%$. The number of lactic acid bacteria increased significantly garlic concentrations at early stages of storage and had no significant differences at later stages. The numbers of proteolytic bacteria, psychrotroph, and fungi increased in proportion to length of storage and garlic concentrations at early stages of storage whereas, the number of bacteria decreased significantly at later stages of storage with increasing garlic concentrations.

• Korean Journal of Veterinary Service
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• v.40 no.2
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• pp.119-131
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• 2017

Among different types of spoilage, microbial contamination can cause feed decomposition, which results in decreases in feed intake and productivity, infection, and breeding disorder. During the storage time, various microbes have a chance to inoculate with depreciation of feed and to infect the animals. We investigated bacteria that inhabit diverse feed ingredients and complete feed which have been stored for a few months. We isolated and identified 30 genera and 62 species of bacteria. Among these 62 species, 21 species were of non-pathogenic bacteria, 18 species were of pathogenic bacteria, 9 species were of opportunistic pathogens, and 14 species were of unknown bacteria. Pantoea allii and 24 species showed proteolytic enzyme activity. We also confirmed that 6 species including Pseudomonas psychrotolerans showed ${\alpha}$-amylase activity, and 29 species including Burkholderia vietnamiensis showed cellulase activity. Microbacterium testaceum and 3 species showed resistance to Ampicillin, Kanamycin, Streptomycin, Gentamicin, Carbenicillin, and Erythromycin ($50{\mu}g/mL$). Using mealworm larvae (Tenebrio molitor L.) as a model for pathogenicity, we confirmed that 8 species including Staphylococcus xylosus had pathogenicity for mealworm larvae. Especially, Enterobacter hormaechei, Staphylococcus xylosus, and Staphylococcus hominis were reported as being pathogenic for humans. This research suggests that hygienic management of animal feed is essential because beneficial and harmful bacteria can inhabit animal feed differently during storage and distribution.

• Korean Journal of Microbiology
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• v.8 no.2
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• pp.53-64
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• 1970

In order to study ecology of microorganisms during Takju brewing, microflora changes were examined fromm the start to the sixth day of Takju fermentation in 24 hours intervals. Takju made from rice, flour and dried sweet potato in a liter volume open container at the laboratory and a sanple of Takju brewing factory were studied for their microflora and their changes during fermentationl together with a sample of Kokja. Results obtained were as follows ; 1. The followings were the identified microorganisms in Kokja. The molds ; Absidia spinosa, Aspergillus parasiticus. The yeasts ; Candida melinii, Candida Solani, Hansenula anomala. The bacteria ; Luctobacillus casei, Leuconostoc mesenteroides, Bacillus subtilis, Bacillus pumilus. 2. Torulopsis inconspicua, Lactobacillus casei, Leuconotoc mesenteroides, Bacillus subtilis, Bacillus pumilus were isolated from main mash of laboratory-made Takju samples. The yeast, Torupsis inconspicua which was not present in Kokja and, probably of a contaminant yeast, dominated the yeast flora of Takju mash of rice, flour and sweet potato of labotatory brewing. The laboratory brewing lost also always showed large population of lactic acid bacteria flora. 3. None of the wild yeasts which were present in Kokja appeared in Takju mashes. The Kokja appears to be of no use as the yeast source for Takju fermentation. Also the Kokja appears to be of not so effective amylolytic and proteolytic enzyme sources considering the microflora characteristics. Probably the major role of Kokja in Takju fermentation may be to contribute in taste formation. 4. Inoculation of Sacharomyces cerevisiae into the mash to the level of $10^7$ ml at the start of fermentation greatly changed the ecological aspects eliminating conditions of rather slow rising of natural contaminant yeast populaiton and fermentation which might give rise to prosperity of lactic acid and Bacillus bacteria that would be avoidable. 5. Examination of microflora of the large factory scale Takju fermentation showed the quite similar pattern of microflora and their changes to that of the cultured yeast-inoculated laboratory batch Takju fermentation. The cultured yeast dominated as the only predominant microflora, and the lactic acid bacteria flora were completely suppressed and aerobic bacteria, greatly. Probably this may be the regular microflora pattern of normal Takju fermentation. The role of lactic acid bacteria and aerobic bacteria in Takju fermentation may not be clear yet from this experiment alone.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.897-904
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• 2007

The aim of this paper is to discuss the methodology of our investigation of the dynamics of protein degradation and the total in situ protealytic activity in meso/eutrophic, eutrophic, and hypereutrophic freshwater environments. Analysis of the kinetics and rates of enzymatic release of amino acids in water samples preserved with sodium azide allows determination of the concentrations of labile proteins $(C_{LAB})$, and their half-life time $(T_{1/2})$. Moreover, it gives more realistic information on resultant activity in situ $(V_{T1/2})$ of ecto- and extracellular proteases that are responsible for the biological degradation of these compounds. Although the results provided by the proposed method are general y well correlated with those obtained by classical procedures, they better characterize the dynamics of protein degradation processes, especially in eutrophic or hypereutrophic lakes. In these environments, processes of protein decomposition occur mainly on the particles and depend primarily on a metabolic activity of seston-attached bacteria. The method was tested in three lakes. The different degree of eutrophication of these lakes was clearly demonstrated by the measured real proteolytic pattern and confirmed by conventional trophic state determinants.

• Korean Journal of Microbiology
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• v.37 no.4
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• pp.239-244
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• 2001

We isolated a Myxobacteria strain from a soil sample obtained from Mt. Daedoon located in Choongnam, Korea. This strain, ARJ, secreted slime while swarmed on the surface of CT medium. It produced greenish yellow pigment in liquid or solid media, and the swarming edge showed green florescence under U. V. at 366 nm. It formed fruiting bodies when nutrient was exhausted, which is one of the most imkportant characteristics of Myxobacteria. The fruiting bodies did not have a stalk and consisted of naked myxospores when examined under the scanning electron microscope. These traits lead us to believe that this strain is very close to Myxococcus virescens. It showed antimicrobial activity, especially against Gram positive bacteria. Culture filtrate showed the activity but this was not due to protein. The culture filtrate also had proteolytic activity in which at least two enzymes are involved.