• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
• /
• pp.372-375
• /
• 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 ).

• 한국미생물·생명공학회지
• /
• 제20권6호
• /
• pp.687-692
• /
• 1992

혼합배양중의 각 미생물의 생균수 측정은 순수배양보다 훨씬 복잡하다. 특히 두 균주의 크기가 비슷한 경우에는 사용할 수 있는 방법이 더 제한된다. 본 연구에서는 두 균의 크기가 비슷한 경우에도 적용될 수 있는 간단한 생균수 측정방법을 개발하였다. 미생물 배양액의 산소흡수속도(OUR)는 세포수에 비례하며 이때의 비례상수인 최대 비산소흡수속도( maximum specific OUR)를 알고 있으면 배양액의 OUR을 측정함으로써 간접적으로 생균수를 구할 수 있게된다. 혼합배양의 경우 산소흡수속도는 각 미생물의 호흡속도의 합이 되며, 각 미생물의 호흡속도가 서로 다르고 또한 온도의존성이 다르다면 호흡속도의 측정을 이용하여 각 생균수를 간접적으로 측정할 수 있다.

• KSBB Journal
• /
• 제13권6호
• /
• pp.644-648
• /
• 1998

In the production of a low cost bacterial insecticide, it is important to produce a high spore concentration using low price substrates. Experiments were carried out to investigate the effects of the addition of mineral salts and glucose, and of dissolved oxygen concentration on the cell growth and spore formation of Bacillus thuringiensis var aizawai using a cheap wheat and soybean meal in the batch culture. The maximum viable cell number was 1.2${\times}$109 CFU/mL at 12 hr culture and spore yield was 54.2% at 74 hr culture using an industrial medium containing 20 g/L wheat meal and 30 g/L soybean meal under 1.0 vvm aeration and 200 rpm agitation. The cell growth and the spore formation were not enhanced by the addition of mineral salts in industrial medium, whereas th addition of 10g/L glucose decreased the cell growth and spore formation. We could obtain a maximum viable cell number of 2.2${\times}$109 CFU/mL and spore number of 1.9${\times}$109 CFU/mL at the dissolved oxygen concentration of 60% of saturation. The spore concentration was enhanced approximately by 2 times as compared to the dissolved oxygen concentration of 50%. In the bench-scale culture, the maximum viable cell and spore number were 2.5${\times}$109 CFU/mL, and 2.2${\times}$109 CFU/mL, respectively under 1.0 vvm aeration and 400 rpm agitation. The spore yield was 88% based on the maximum viable cell number. As a result, it was confirmed that the production of high spore concentration could be obtained by a bench-scale culture using an industrial medium.

• 한국식품저장유통학회지
• /
• 제6권4호
• /
• pp.442-447
• /
• 1999

섬유질이 풍부하고 enthocyanin색소가 풍부한 자색 고구마를 이용하기 위하여 탈지유와 설탕이 들어있는 기본배지에 증자, 박피한 고구마를 첨가한 후 5종(Lactebacillus bulgaricis, Lactobacillus delbruchii sub. sp. lactis, Streptococcus lactis, Bifidobacterium bifidum, Leuconostoc lactis) 의 젖산균주를 배양, 접종하여 호상 요쿠르트를 만들고 자색고구마가 젖산균의 생육과산 생성, 색도에 미치는 영향 및 저장성 등을 조사한 결과 L. bulgaricus균을 배양한 경우가 젖산균의 증식과 산 생성이 가장 빨라 발효개시 12시간만에 1.04 $\times$$10^{9}$CFU/$m\ell$의 생균수와 pH 4.22를 나타냈고 B. bifidum균은 발효개시 24시간까지는 젖산균의 증식이 느리게 이루어져 발효개시 36시간에 달할 때 3.3 $\times$ $10^{8}$ CFU/$m\ell$의 생균수와 pH 5.1을 나타냈다. 발효종료 후 자색고구마를 첨가한 요쿠르트의 자색은 B. bifdum균에 의한 요쿠르트제조시 색도가 가장 안정하였고 Leuc. lactis, L. delbruechii sub. sp. lactis, L bulgaricus순으로 안정하였으며 St. lactis균에 의한 요쿠르트는 자색의 색소 소실이 가장 많았다. 2~3$^{\circ}C$에서 저장시 저장 2주까지 pH의 변화는 거의 없었고 생균수의 변화는 L. bulgaricus와 L. delbruechii sub. sp. lactis균에 의해 제조된 요쿠르트는 저장 1주까지는 변화가 없었으나 그 이후는 약간 감소하였으며 St. lactis균과 B. bifidum 균은 저장 1주까지 저온에서도 생균수가 소량 증가함을 보여주었다. 색도는 저장 2주 후 B. bifidum균에 의한 요쿠르트 제조시 자색도가 많이 소실되었고 L. delbruechii sub. sp. lactis균에 의한 요쿠르트가 가장 안정하였다.

• 한국식품위생안전성학회지
• /
• 제12권3호
• /
• pp.188-194
• /
• 1997

The growth inhibition effect of Orally administrated yogurt ACE and Metchnikoffupon E. coli O157:H7 and S. typhimurium inoculated into gastric lumen of rabbits was in vestigated. The rabbits challenged with each 1 $m\ell$ of suspension containing 108 CFU/$m\ell$ of the pathogens were divided into 4 groups by the interval of yogurt administration: A group; preadministrated 7 days before inoculation of the pathogens and fed daily; B group; administrated daily after inocjlation of the pathogens, C group; administrated every 3 days after inoculation of the pathogens; Control group, not fed after inoculation of the pathogens. Each 3 $m\ell$ of yogurt containing 109 CFU/$m\ell$ was orally administrated into rabbits. All yogurt administrated groups (A, B, c) chowed growth ingibition effect on E. coli O157:H7 in one day after inoculation of the pathogen by the level of 0.8~1.0 log CFU/g, compared with the result differences between the control group and the yogurt administrated groups. In the control group after 5 days of inoculation, the number of colonized pathogens was 105~106 CFU/g, whereas 103~104 CFU/g was detected in the yogurt administrated groups. After 10 days of inoculation, the viable pathogen number per gram (g) of the rabbit feces was 103 CFU/g in the control group, whereas the number below 101 CFU/g was detected in the group A, and 102 CFU/g in the control group, B and C. The growth inhibition effect of yogurt administration on E. coli O157:H7 was highly increased in the order of A, B, and C group. The same effect on S. typhimurium was observed at the level of 2 log CFU/g in the Metchnikoff yogurt administrated groups, compared with the control group result in one day after inoculation of the pathogen. In 7 days after inoculation of the pathogen, the viable number was increasingly decreased, and finally after 15 days no viable cell of S. typhimurium was discharged into the fecal samples in the group A, and the mean level of 10* CFU/g was detected in the group B, but there was no growth inhibition effect in the group C. The growth inhibition effect on S. typhimurium was observed at the same level of viable cell number between the yogurt ACE administrated groups and the control group in 5 days after inoculation. But, after 10 days of inoclation the viable cell number was started to decrease, and the viable cell of S. typhimurium was not discharged from rabbit intestinal contents after 15 days of inoculation in the yogurt ACE administrated groups. In such a case that yogurt was administrated in order to prevent the pathogens, pre-administration on a daily basis one week before inoculation of the pathogens exerted considerable effect in growth inhibition. In comparison with two kinds of yogurt tested in this study, the growth inhibition effect on two kinds of pathogens was observed more highly in the Metchnikoff administated group than the ACE administrated group.

• Journal of Periodontal and Implant Science
• /
• 제29권1호
• /
• pp.265-276
• /
• 1999

This study was performed to evaluate the effect of hydrogen peroxide-producing Lactobacillus acidophilus V-20onthe replication of periodontal pathogens, Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. When A. actinomycetemcomitans and P. gingivalis were incubated alone and in the combination with L. acidophilus V-20, the viable cell numbers of A. actinomycetemcomitans and P. gingivalis were compared between those cultures. The effect of S. mutans, E. durans, and L. lactis on the replication of A. actinomycetemcomitans and P. gingivalis was also evaluated. The change of periodontal indexes(probine depth, gingival index, GCF volume) and the viable cell numbers of A. actinomycetemcomitans and black pigmented bacteroides in subgingival plaque sample were evaluated following gargling of fermented milk made from L. acidophilus V-20 for 1 month on patients with periodontal disease in maintenance phase. In the mixed culture of L. acidophilus V-20 and A. actinomycetemcomitans or P. gingivalis, the replication of A. actinomycetemcomitans or P. gingivalis wascompletely inhibited. But in the mixed culture of P. gingivalis and hydrogen peroxide-nonproducing Lactobacillus casei, the viable ceil numbers of P. gingivaliswas not decreased when compared with the numbers in the mixed culture of P. gingivalis and L. acidophilus V-20. In the mixed culture of A. actinomycetemcomitans and S. mutans, E. durans, or L. lactis, the viable cell number of A. actinomycetemcomitans was not almost changed when compared with the numbers in the culture of A. actinomycetemcomitans alone. And in the mixed culture of P. gingivalis and E. durans or L. lactis, the viable cell numbers of P. gingivaliswas not almost changed compared with the counts in the culture of P. gingivalis alone. But the replication of P. gingivalis was completely inhibited in the mixed culture of P. gingivalis and S. mutans. When the change of periodontal indexes following gargling of fermented milk was compared with baseline, probing depth and gingival index were not changed, but GCF volume was significantly decreased(p<0.05). And when the viable ceil numbers of microorganisms in subgingival plaque sample were compared with baseline, total viable ceil number was almost unchanged and the viable cell numbers of A. actinomycetemcomitans and black pigmented bacteroides were significantly decreased(p<0.05). These results suggest that L. acidophilus V-20 inhibit the replication of A. actinomycetemcomitans and black pigmented bacteroides by the formation of hydrogen peroxide.

• 치과방사선
• /
• 제27권1호
• /
• pp.107-122
• /
• 1997

Radiation sensitivity data was generated for two human cancer cell lines(KB, RPMI 2650) and human primary gingival fibroblast was tested three times using a viable cell number counting with a hemocytometer, MTT(3-[4,5-Dimethylthiazol2-yl]-2,5-diphenyl tetrazolium bromide) assay, and LDH(Lactate dehydrogenase) assay. Single irradiation of 2, 4, 6, 10, 15, 20Gy were applied to the tumor cell lines and the primary cultured gingival fibroblast The two fractions of 4Gy and 10Gy were seperated with a 4 hour time interval. The irradiation was done with 241.5cGy/min dose rate using /sup 137/Cs MK cell irradiator at room temperature. The obtained results were as followed : 1. There was significantly different viable cell numbers as the amount of radiation dose on the tested cells were cell number counted with a hemocytometer. In fractions, there were more viable cells remaining. 2. Phase-contrast microscopically, radiation-induced morphologic changes were pronounced on the tumor cells, however, almost no differences on the gingival fibroblast. 3. There was significantly different absorbance at 2Gy on RPMI 2600, 4Gy on KB and GF in MTT assay. In fractions, the absorbance was significantly higher on KB. 4. The level of extracellular LDH activity in the experimental group was significantly higher in the 2-4Gy than the control group. 5. The total level of extracellular and intracellular LDH activity was decreased as increased amounts of radiation dose was applied.

• 한국축산식품학회지
• /
• 제20권1호
• /
• pp.21-29
• /
• 2000

This study was carried out to investigate the fermentation characteristics and storage of set-type yoghurt added mugwort extracts(AME) such as pH, growth of lactic acid bacteria, number of viable cells, viscosity, and sensory characteristics during 24 hours fermentation and 15 days storage. Addition of mugwort extracts was grown rapidly of lactic acid bacteria rather than that of control and also 4 or 8% AME groups were grown similar to control. The drop of AME pH of broth was less compared with control during incubation of lactic acid bacteria. The growth of lactic acid bacteria during incubation of AME yoghurt was not different of viable cell count between AME group and control in beginning time, but the viable cell count of AME groups were increased depended opon addition quantity of AME in ending time. Addition of mugwort extracts was not affect on pH change during yoghurt fermentation and increased a lactic acid bacteria number as well as no effect of yoghurt fermentation in ending time. The viscosity of yoghurt was almost not changed 3 hours after yoghurt mix and increased rapidly 6 hours after yoghurt mix. Although control and 0.5% AME group showed maximum viscosity at 18 hours of fermentation, 1 and 2% AME group showed linear increase until 24 hours of fermentation. Mugwort did not affect pH and viable cel number of lactic acid bacteria during 15 days storage 24 hours after fermentation. Sensory evaluation of the AME yoghurt showed that flavour, texture and acid taste were not affected by addition of mugwort. However, the appearance and taste were dropped by addition of mugwort.

• 한국자원리싸이클링학회:학술대회논문집
• /
• 한국자원리싸이클링학회 2001년도 정기총회 특별강연 및 춘계학술연구발표회(2)
• /
• pp.121-125
• /
• 2001

For the probiotic feed production, aerobic liquid fermentation of pulverized food wastes was attempted with a yeast Kluyveromyces marxianus. After grinding finely, optimal fermentation conditions of the substrate was investigated by shaking culture. The most active growth of the yeast was shown at solid content of 10%. The proper addition of urea(0.5g/l), o-phosphate(0.4g/l), molasses(4g/l), and yeast extract (1g/1) increased cell growth rate and viable cell count. For optimizing, the nutrients were all added to substrate and fermentation was carried in 2 litre jar fermenter. For the stimulation of hydrolyzing enzyme excretion, mixed culture with Aspersillus oryzae was also conducted. In 12 hours of fermentation, viable cell count of the yeast Kluyveromyces marxianus amounted to the number of 1.4 $\times$10$^{10}$ /1 in the culture medium.

• 한국식품영양학회지
• /
• 제13권1호
• /
• pp.71-77
• /
• 2000

New type yogurt base were prepared from milk added with skim milk powder or purple sweet potato, and fermented by lactic acid bacteria (Streptococcus thermophilus and Bifidobacterium infantis, 1:1, v/v). The yogurt proudcts were evaluated for acid production(pH, titratiable acidity), number of viable cell, viscosity, sensory properties, and color value. The composition of some organic acids was also analyzed by GC. The acid production slightly decrerased by addition with purple sweet potato. There was no significant difference in viable cell counts between control (yogurt added with only skim milk powder) and yogurt added with purple sweet potato, and viable cell counts of all samples were above 9.08 log cfu/ml. Viscosity of yogurt added with purple sweet potato(36,800∼46,000 centipoise) was higher than that of yogurt added with only skim milk powder(32,200 centipoise). The overall sensory score of yogurt added with purple sweet potato(38.6%, dry base) was the best of tested yogurt. The major organic acid of yogurt added with purple sweet potato was lactic acid. its content was 0.997∼1.203%. malic acid, succinic acid, oxalic acid, and fumaric acid were analyzed out a little. Lightness and yellowness decreased by addition with purple sweet potato but redness increased. Total color difference($\Delta$E) with yogurt addition with purple sweet potato and only skim milk powder were very high(above 11.46).