• Korean Journal of Microbiology
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• v.38 no.3
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• pp.180-185
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• 2002

The direct viable count (DVC) and plate count (PC) methods was used to measure the number of bacteria in potable groundwater samples collected from bottled water from the market, mineral water, and edible groundwater near the urban areas and the stock farming congested areas. As a result, the number of living bacteria by DVC was comprised 30~80% of the total direct count (TDC), whereas the number of living bacteria by PC was around l~30% of DVC. Such results show that viable but non-culturable (VBNC) bacteria exist in the potable groundwater with high percentages. On the other hand, upon measuring the value from the conventional nutrient broth (NB), $10^-2$ fold diluted nutrient broth (DNB), and R2A broth, the values from the DNB and R2A showed 2~50 times higher than the conventional NB medium. These results indicate that oligotrophic bacterial groups which can multiply in the low nutrient broth abundantly exist in the oligotrophic environment like potable groundwater.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.372-375
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• 2000

Lactobacillus cristatus KLB 46 isolated from Korean woman was grown on supplemented whey medium and medium compositions were optimized for maximum viable cell count. Among the nitrogen sources tested, beef extract yielded the highest viable cell number. When corn steep liquor was applied as an additional nitrogen source, the viable cell number was highest $(3.11{\times}10^9\;CFU/ml)$ in the medium containing 50g/ l corn steep liquor and 10g/ l beef extract. The highest viable cell $count(5.00{\times}10^9\;CFU/ml)$ was obtained from the supplemented whey medium that contains beef extract(10g/ l ), corn steep liquor(50g/ l ), tween 80(0.1%, v/v) and trace amounts of sodium acetate(5g/ l ), dipotassium phosphate(2g/ l ), magnesium sulfate(0.1g/ l ), and manganese sulfate (0.05g/ l ).

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.205-209
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• 2006

For measuring the viable cells in lakes, quantitative direct viable count (qDVC) method is applied. In the qDVC process, the final concentration of glycine is fixed as 2%. For confirming the effectiveness of qDVC for enumerating the viable cells, the viable bacterial numbers were measured by plate count, CTC reduction method and qDVC method at 5 different lakes. Among these 3 methods, the bacterial numbers by qDVC is $2.4{\sim}6.0$ times higher than those by the other 2 methods. And by the qDVC method, the viable cells were easily discriminated from dead or dormant cells.

• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1558-1562
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• 2007

To elucidate the influence of pipe materials on the VBNC (viable but nonculturable) state and bacterial numbers in drinking water, biofilm and effluent from stainless steel, galvanized iron, and polyvinyl chloride pipe wafers were analyzed. Although no HPC (heterotrophic plate count) was detected in the chlorinated influent of the model system, a DVC (direct viable count) still existed in the range between 3- and 4-log cells/ml. Significantly high numbers of HPC and DVC were found both in biofilm and in the effluent of the model system. The pipe material, exposure time, and the season were all relevant to the concentrations of VBNC and HPC bacteria detected. These findings indicate the importance of determining the number of VBNC cells and the type of pipe materials to estimate the HPC concentration in water distribution systems and thus the need of determining a DVC in evaluating disinfection efficiency.

• KSBB Journal
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• v.26 no.6
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• pp.529-532
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• 2011

Whey based medium was optimized for the production of viable Lactobacillus crispatus KLB 46 isolated from the vagina of Korean women. Among the various nitrogen sources such as yeast extract, beef extract, and proteose peptone no. 3 supplemented to whey, beef extract showed the highest viable cell production. The addition of Tween 80 to the whey based medium increased viable cell concentration. As beef extract supplementation is not economically attractive, corn steep liquor was added as a supplementary nitrogen sources. When corn steep liquor was supplied with beef extract with the ratio 5 : 1, the viable cell count was $3.11{\times}10^9$ CFU/mL. Also, the addition of mineral salts containing sodium acetate (5 g/L), potassium phosphate dibasic (2 g/L), magnesium sulfate (0.1 g/L) and manganese sulfate (0.05 g/L) to the whey medium increased viable cell count further ($5.00{\times}10^9$ CFU/mL).

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.181-186
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• 2003

This study was performed to analyze quantitatively the number of living bacteria in forest soil samples collected from Mt. Keryong using improved direct viable count (DVC) and plate count (PC) methods. The number of living bacteria by DVC comprised 18～44% of the total direct count (TDC), whereas the number of living bacteria by PC was less than 1% of TDC. These results showed that viable but non-culturable (VBNC) bacteria existed in the soil with high percentages. Besides, DVC was proved to make it possible to make a quantitative detection of the VBNC bacteria. On the other hand, upon measuring the value from the conventional nutrient broth (NB) and $10^{-2}$ folded diluted nutrient broth (DNB), the values from the DNB showed 5 to 10 times higher than those from the conventional NB medium. These results indicate that oligotrophic bacterial groups, which could multiply in the low nutrient broth, abundantly exist in the soil ecosystem. It would also be possible to apply this kind of method to other substrate to make a quantitative detection of soil bacterial groups.

• Food Science of Animal Resources
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• v.21 no.2
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• pp.133-141
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• 2001

Adherence of probiotic bacteria to intestinal epithelium is found to be the most principal characteristics among the various physiological functionality. This study was conducted to investigate the effect of bifidobacterial growth properties and condition on the Caco-2 cell adherence and to construct a basic data on adherence-related research. Among 20 strains of bifidobacteris tested, when measured by cell surface hydrophobicity(CSH) and cell agglutination(CA), Bifidobacterium bifidum ATCC29521, Bif. adolescentis K8, and Bif. infantis K9 were selected. Using these strains, variations of Caso-2 cell adherence depending upon experimental condition were analyzed. The results obtained are as follows : Even though Bif. bifidum ATCC29521, Bif. adolescentis K8, and Bif. infantis K9 reached more 85% cell surface hydrophobicity there was no significant difference in cell agglutination, when reached 31.54$\pm$0.54mg/ml. By direct count method for adherence, viable cell count of M3, K1, K2, K8, K9 and K10 reached more 100 counts per 100 Caco-2 cells. When Bif. bifidum ATCC29521, Bif. adolescentistis K8, and Bif. infantis K9 were used to compare the adherence depending upon viable cell counts, reaction time, and growth phase, the more viable cell count, and the more adhered cell counts, the less adherence percentage. In addition, there was no difference in adherence percentage of bifidobacteria when bifidobacteria was incubated from 1 to 8 hrs after Caco-2 cells already formed monolayer. Considering of the effect of growth phase of bifidobacteria on adherence variation, all strains showed the highest adherence during the early stage of stationary phase. In conclusion, adherence of bifidobacteria was affected by strain specificity, viable cell count, and growth activity.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.5
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• pp.525-535
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• 2002

The purposes of this study were to evaluate the adherence of bacteria on various denture base resin materials and effects of chitosan, added to denture base materials on bacterial adherence. PMMA denture base resin such as heat-cured Vertex-RS, self-cured Vertex-SC and 4-META denture base resin such as heat-cured Meta-Dent, self-cured Meta-Fast were used in this study Samples were divided into two groups the denture base resin with chitosan, without chitosan Streptococcus mutans and Lactobacillus casei were used in this study. The surface of samples was observed by SEM. When chitosan was added to M17 and MRS broth, viable cell count of bacteria was reduced. Viable cell count of Streptococcus mutans on the samples decreased as follows : Meta-Dent, Vertex-SC, Meta-Fast, Vertex-RS. Viable cell count of Lactobacillus casei on the samples decreased as follows: Vertex-RS, Meta-Dent, Meta-Fast, Vertex-SC. The resin with chitosan showed lower adherence of bacteria than without chitosan. The images of SEM showed that the surface of the resin with chitosan was rougher than that of without chitosan. These results showed that the denture base resin materials with chitosan have rougher surface than without chitosan, but less bacteria adhered on them.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.696-701
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• 2013

Flounder Verasper moseri Jordan et Gilberu sikhae is one of the traditional Korean fermented food. Microbiological, chemical, and biogenic amine analyses were carried out to evaluate the quality of commercial flounder sikhae and establish standardization. The quality characteristics were analyzed in terms the salinity, volatile basic nitrogen, pH, amino-N, TBA value, biogenic amine, viable cell count, and lactic acid bacteria. Quality evaluation of commercial flounder sikhae revaled an average pH of 4.84, volatile basic nitrogen of 43.47 mg/100 g, amino-N of 213.04 mg/100 g, salinity of 5.77 %, viable cell count of $10^6-10^7CFU/g$, viable lactic acid bacteria count of $10^6-10^7CFU/g$ and biogenic amine level of 0.70-47.34 mg/kg.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.2
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• pp.128-132
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• 2001

Bacterial vaginosis can be treated by restoring the normal vaginal flora using lactobacilli. Lactobacillus crispatus KLB46 that was isolated from the human vagina has a string antimicrobial activity and was grown in a batch and in a continuous fermentor. During batch cultivation, the maximum specific growth rate of L. crispatus KLB 46 was 0.63h(sup)-1 and the highest viable cell count (1.9$\times$10(sup)9 CFU/mL) was obtained at pH 5.5. L. crispatus KLB 46 did not grow well at either pH 3.5 or 7.5. During continuous cultivation, the highest viable cell count (1.53$\times$10(sup)9 CFU/mL) was obtained at a dilution rate of 0.32h(sup)-1, and was 7.33$\times$10(sup)11 CFU L(sup)-1 h(sup)-1, that is approximately 5 times higher than that obtained from batch culture.