• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.532.1-532
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• 1986

유산균이 생성하는 polysaccharide 에 관한 연구의 일환으로서 L. casei YIT 9018 SKD-0007, L. bulgaricus SKD-0003, sir. faecalis SKD-1007, str. thermophilus SKD- 1005, str. thermophilus 510 SKD-1006등을 탈지유에 배양하면서 polysaccharide 생성에 의한 배양액의 점도 변화를 검토하였다. 이러한 다당류가 Antitumor로서의 활성과 제암효과를 가지며 인체내의 생리효과를 고양시킨다고 보고되어 있는바 다당류가 최대로 생성되는 조건을 찾는 것을 본 실험의 목적으로 하였다. 다당류의 생성을 측정하는 방법으로서 배지로는 10% 환원탈지유와 12% 환원전지유를 선택하였으며 Brookfield Viscometer를 사용하여 배양액의 점도를 경시적으로 측정하였다. 시험균 중에서 str. thermophilus 510 SKD-1006이 가장 높은 점도를 나타내었는데 41$^{\circ}C$ 배양 5일째에 5000 cps였고 다른균에 비해서 1000cps이상 높았다. 접종량이 증가할수록 점도도 증가하였으며 14%이상의 탈지유 농도에서는 7000cps를 나타냈다. 탈지유와 전지유 배양액 모두 의가소성 유체의 유동 양식을 나타내었는데 12% 환원전지유 배양액은 최대점도값이 2500 cps에 불과하였으며 배양 2일째에 최대점도 값에 도달하여 그 이후로 급격한 감소현상을 보였다.

• Journal of Dairy Science and Biotechnology
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• v.30 no.2
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• pp.69-74
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• 2012

This study was performed to determine by the ability of the mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus to ferment Dioscorea opposita Thunb. (yam) and to evaluate the nutraceutical value of fermented yam. The titratable acidity (TA) value increased from 2 to 6% with increased concentrations in both raw yam and extracted lactic acid bacteria (LAB) fermented yam (LFY). The viable cell counts and the allantoin and diosgenin contents were higher in raw LFY at large concentrations (6%) than in extracted LFY samples at all fermentation periods up to 32 h. Based on these data, it confirmed that raw yam fermented by the combination culture of L. bulgaricus and S. thermophilus for various fermentation periods favors the symbiotic growth of LAB and results in higher nutraceutical content.

• Journal of Industrial Technology
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• v.1
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• pp.61-66
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• 1981

In order to use as a starter after drying, optimum growth conditions of Str. thermophilus and L. bulgaricus were investigated. The results were as follows. The growth of Str. thermophilus was reached at stationary phase after 12 hours incubation and L. bulgaricus was after 6 hours. Str. thermophilus was grown well, in the medium containing 10% of skim milk, 2% of sucrose, 0.1% of KCl and 0.015% (v./v.) of soy-sauce. In the case of L. bulgaricus, 10% of skim milk, 2% of glucose, 0.5% of bacto-peptone, 0.1% of $K_2HPO_4$ and 0.02% of pyridoxine was suitable for the maximum growth.

• Food Science of Animal Resources
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• v.25 no.1
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• pp.84-91
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• 2005

We investigated fermentation characteristics and the amount of exopolysaccharide (EPS) produced, and the correlation between EPS and rheological properties in stirred yogurt fermented with Streptococcus thermophilus St-Body 1. The changes of pH and lactic acid concentrations of yogurt showed different patterns according to fermentation temperatures. About 20 to 40% of lactose was utilized during 6 hrs incubation. The higher number of lactic acid bacteria was obtained at 31℃ incubation temperature rather than other incubation temperatures. The higher amount of EPS was produced at 12 hr or 24 hr rather than other incubation period at the same fermentation temperatures. The viscosity continuously increased during the fermentation period, however the syneresis of yogurt was shown the lowest value at 37℃ for 30 hrs incubation. In physical properties, the hardness and adhesiveness increased continuously with decreasing cohesiveness and elasticity as incubation process was extended. The stirred yogurt fermented with S. thermophilus St-Body 1 at 37℃ for 24 hr resulted in the highest score at each sensory evaluation category.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1978.04a
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• pp.96.4-96
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• 1978

발효유 제조에 있어 skim milk 대체원료로 soy-milk 및 defatted soymilk를 사용하여 명종유산균 (S. thermphilus, L. acidophilus, L. bulgaricus, S. thermophilus＋L. acidophilus, S. thermophilus＋L. bulgaricus, L. acidophilus＋L. bulgaricus) 의 증식 조건을 조사한 결과 soymilk의 균수는 skim milk와 defatted soy milk에 비하여 별 차이가 없었으나 적정산도는 현저히 낮았다. 또한, soymilk 및 defatted soy milk에 2％ lactose 첨가시 유산균 증식이 양호하였다.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.37.1-37.1
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• 2008

• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.151-156
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• 2002

This study was performed to obtain the thermostable $\beta$-glycosidase producing bacteria from hot spring of volcanic area at Atagawa in Japan. KNOUC 202 was selected because it showed thermostable $\beta$-glycosidase activity in sodium phosphate buffer(pH 6.8) at $70^{\circ}C$ for 4h, and it was identified. The strain was aerobic, asporogenic bacilli, immobile, gram negative, catalase positive, oxidase positive, and pigment-producing. Optimum growth was at $70~72^{\circ}C$, pH 7.0~7.2, and it could grow in the presence of 3% NaCl. The main fatty acids in cell were iso-15:0 and iso-l7:0. 16S rRNA sequence of KNOUC 202 showed 99.9% similarity with that of Thermus thermophilus ATCC 27634(HB8). Based on morphological, physiological, biochemical characteristics, cellular fatty acids profile and 16S rRNA sequence analysis, KNOUC 202 was identified as Thermus thermophilus.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.101-104
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• 1995

We isolated sixty lactic acid bacteria(LAB) from lactic fermented products. Among 60 isolates of LAB, 30 isolates were identified as Lactobacillus casei ssp.(5 strains), Lactobacillus acidophilus(2 strains), Lactobacillus delbrueckii ssp. bulgaricus(6 strains), Lactobacillus plantarum(4 strains), Streptococcus salivarius ssp. thermophilus(11 strains), and Streptococcus faecalis(2 strains). The acid tolerance and bile resistance of 30 LAB were determined. Because the acid tolerance was affected by the initial cell concentrations, the analysis of covariance could be used to remove the effect of initial cells on acid tolerance when testing for differences in acid tolerance among six species. Viability of LAB under acidic condition, pH 3 for 2 hours at $37^{\circ}C$, was significantly different among the species. L. casei and L. acidophilus strains showed great viability, but L. bulgaricus and S. thermophilus strains were very weak in acid tolerance.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.164-172
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• 1989

The formation of galactooligosaccharides by transgalactosidation reactions during hydrolysis of lactose by the ${\beta}-galactosidase$ from Streptococcus thermophilus 510 was investigated. Three oligosaccharides were detected during hydrolysis. It was found that the optimum conditions for the production of oligosaccharides was 40% lactose treated with ${\beta}-galactosidase(50\;ONPG\;units/ml)$ at $37^{\circ}C$ for 4 hours. The oligosaccharides formed accounted for 30% of the total sugars when the lactose had been 94% hydrolysed. 69% of the oligosaccharides were identified as $6-o-{\beta}-D-galactopyranosyl-D-glucose(allolactose)$ and 23% as $6-o-{\beta}-D-galactopyranosyl-D-galactose(isogalactobiose)$. The separation of galactooligosaccharides by the use of Bio-Gel P-2 gel permeation chromatography was also studied.

• KSBB Journal
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• v.6 no.4
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• pp.413-424
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• 1991

The optimal condition for manufacturing the yoghurt by using B. bifidum and L. acidophilus was studied. Optimal growth condition of B. bifidum and fermentation effects of B. bifidum, L. acidophilus and Str. thermophilus in mixed culture were investigated separately. Fermentation conditions of B. bifidum were optimized in 12% reconstitued skim milk. The addition of BIOS 2000 to 12% skimmilk was effective on the growth and acid production of B. bifidum. There was asymbiosis among B. bifidum, L. acidophilus and Str. thermophilus in mixed culture which resulted in higher viable cell numbers and acid production. The optimum production of yoghurt was achieved by incubation at $37^{\circ}C$ for 8 hours with 5% mixed starter culture (B. bifidum+L.acidophilus+Str. thermophilus). In this case the effective ratio of B. bifidum: L. acidophilus: Str. thermophilus was 2:1:1 on both acid production and viable cell counts.