• Journal of Microbiology and Biotechnology
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• v.33 no.8
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• pp.1076-1083
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• 2023

Poly(3-hydroxybutyrate) (PHB) is a biodegradable and biocompatible bioplastic. Effective PHB degradation in nutrient-poor environments is required for industrial and practical applications of PHB. To screen for PHB-degrading strains, PHB double-layer plates were prepared and three new Bacillus infantis species with PHB-degrading ability were isolated from the soil. In addition, phaZ and bdhA of all isolated B. infantis were confirmed using a Bacillus sp. universal primer set and established polymerase chain reaction conditions. To evaluate the effective PHB degradation ability under nutrient-deficient conditions, PHB film degradation was performed in mineral medium, resulting in a PHB degradation rate of 98.71% for B. infantis PD3, which was confirmed in 5 d. Physical changes in the degraded PHB films were analyzed. The decrease in molecular weight due to biodegradation was confirmed using gel permeation chromatography and surface erosion of the PHB film was observed using scanning electron microscopy. To the best of our knowledge, this is the first study on B. infantis showing its excellent PHB degradation ability and is expected to contribute to PHB commercialization and industrial composting.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.117-122
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• 2004

Bacillus sp. $\beta$-mannanase was purified by DEAE-sephadex ion exchange column chromatography. The specific activity of the purified enzyme was 21.57 units/$m\ell$ protein, representing an 95.33-folds purification of the original crude extract. The final preparation thus obtained showed a single band on SDS-polyacrylamide gel electrophoresis. The molecular weight was determined to be 38.9 kDa. Guar gum galactomannan was hydrolyzed by the purified $\beta$-mannanase, and then the hydrolysates was separated by activated carbon column chromatography and Sephadex G-25 gel filtration. The main hydrolysates were composed of D.P. (Degree of Polymerization) 5 and 7 galactomannooligosaccharides. To investigate the effects of guar gum galactomannooligosaccharides on in vitro growth of Bifidobacterium longum, B. bifidum, B. infantis, B. adolescentis, B. animalis, and B. breve, Bifidobacterium spp. were cultivated individually on the modified-MRS medium containing carbon source such as D.P. 5 and D.P. 7 galactomannooligosaccharides, respectively B. longum and B. bifidum grew up l0-fold and 9.8-fold more effectively by the treatment of D.P. 5 galactomannooligosaccharides, compared to those of standard MRS medium. Especially, D.P. 5 was more effective than D.P. 7 galactomannooligosaccharide on the growth of Bifidobacterium spp.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2006.05a
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• pp.264-268
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• 2006

혈당강하 요구르트의 개발을 위해 Streptococcus salivarius subsp. thermophilus와 Lacto-bacillus acidophilus 145, Bifidobacterium infantis 혼합균주에 사균인 FK-23 유산구균, 피니톨, 식이섬유, 백강낭콩 추출 분말, 에리스리톨, 바나바 추출물 등의 기능성 성분을 포함한 요구르트를 제조하여 정상인과 혈당치가 높은 당뇨 환자를 대상으로 간이 임상시험을 실시하였다. 1. 정상인의 식후 혈당치는 일반 요구르트를 섭취했을 때보다 혈당 강하 요구르트 음용시 더 낮게 측정되었으며 임상대상자 대부분에서 동일한 현상이 나타났다. 2. 혈당치가 높은 당뇨환자 10명을 대상으로 식후 혈당치 변화 및 음용기간 중 혈당치 변화를 확인한 결과 혈당 강하 요구르트를 음용하기 전보다 음용 후 혈당치가 식후 30 당증가 억제율도 임상대상자의 80%가 감소하는 효과를 나타냈다. 3. 30일간 혈당 강하 요구르트를 음용한 후 식후 혈당치의 변화를 확인한 결과 음용전보다 음용 후 120분 경과 때, 혈당치가 59 mg/dL 감소하였으며 음용기간이 증가할수록 지속적으로 감소하는 경향을 나타내었다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1186-1191
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• 2004

Bacillus sp. $\beta$-mannanase was purified by DEAE-sephadex ion exchange column chromatography. The partially purified P-mannanase exhibited maximum activity at pH 6.0 and 5$0^{\circ}C$, and was stable at a pH range of 5.5 to 7.0, and at temperature between 30 to 5$0^{\circ}C$. Konjac glucomannan was hydrolyzed by the purified $\beta$-mannanase, and then hydrolysates separated by 1st activated carbon column chromatography and 2nd sephadex G-25 gel filtration. The main hydrolysates were composed of D.P 5 and 7 glucomannooligosaccharides by TLC and FACE method. To investigate the effects of guar gum glucomannooligosaccharides on the in vitro growth of B. longum, B. bifidum, B. infantis, B. adolescentis, B. animalis, and B. breve, Bifidobacterium spp. were cultivated individually on the modified-MRS medium containing carbon SOUTce such as D.P 5, and D.P 7 glucomannooligosaccharides, respectively. B. longum grew up 4.6-fold and 5.3-fold more effectively by the replacement of D.P 5 and 7 glucomannooligosaccharides as the carbon source in a comparasion of standard MRS. Also, B. breve and B. animalis slightly grew up by the treatment of D.P 5 glucomannooligosaccharide.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.12
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• pp.1548-1553
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• 2008

This study was concerning various physiological activities of agar hydrolysates. All agar hydrolysates showed strong antimicrobial activity against Bacillus subtilis and Bacillus cereus. Also, the agar hydrolysates prepared at the temperature of $110^{\circ}C$ or $120^{\circ}C$ showed antimicrobial activity against St. aureus and E. coli. Among the agar hydrolysates, several hydrolysates treated with citrate or malate at $110^{\circ}C$ or $120^{\circ}C$ conditions showed tyrosinase activity inhibition, and their inhibition rates of tyrosinase activity were about 80%. Some tested samples treated with 0.5% organic acid at $100^{\circ}C$ or $110^{\circ}C$ inhibited the growth of cancer cell. Two agar hydrolysates prepared with 0.5% citrate and lactate at $110^{\circ}C$ for $180^{\circ}C$ min had relatively high cancer cell growth inhibition among the tested samples. The agar hydrolysates treated with citrate and lactate at $110^{\circ}C$ for 180 min obtained the main peaks of six and seven from Sephadex G-15 column chromatography. Among the main peaks, the cancer cell growth inhibition of C-3 and L-3 fractions were higher than that of other fractions.

• Journal of Applied Biological Chemistry
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• v.51 no.6
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• pp.272-276
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• 2008

Purification and some properties of Xylogone sphaerospora ${\beta}$-mannanase were reprevious previous paper. Locust bean gum galactomannan was hydrolyzed by the purified ${\beta}$-mannanase, and then the hydrolysates was separated by activated carbon column chromatography. The main hydrolysates were composed of D.P. (Degree of Polymerization) 4 and 6 galactosyl mannooligosaccharides. For elucidate the structure of D.P 4 and 6 galactosyl mannooligosaccharides, sequential enzymatic action was performed. D.P 4 and 6 were identified as ${Gal^2}{Man_3}\;(6^2-mono-O-{\alpha}-D-galactopyranosyl-4-O-{\beta}-D-mannotriose)$ and ${Gal^2}{Man_5}\;(6^2-mono-O-{\alpha}-D-galacto- pyranosyl-4-O-{\beta}-D-mannopentaose)$. To investigate the effects of locust bean gum galactosyl mannooligosaccharides on in vitro growth of Bifidobacterium longum, B. bifidum, B. infantis, B. adolescentis, B. animalis, B. auglutum and B. breve. Bifidobacterium spp. were cultivated individually on the modified-MRS medium containing carbon source such as D.P. 4 and D.P. 6 galactosyl mannooligosaccharides, respectively. B. longum and B. bifidum grew up to-fold and 6.6-fold more effectively by the treatment of D.P. 6 galactosyl mannooligosaccharides, compared to those of standard MRS medium. Especially, D.P. 6 was more effective than D.P. 4 galactosyl mannooligosaccharide on the growth of Bifidobacterium spp.