• 한국식품영양학회지
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• 제6권3호
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• pp.208-210
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• 1993

In order to know the influences of heat treatment of yoghurt on pH, $\beta$-galactosidase and viable cells, yoghurt sample was made by general method with Lactobacillus bulgaricus and Streptococcus thermophilus, and the changes in pH, $\beta$-galactosidase-activity and viable cell-count were determined during heating at 55$^{\circ}C$ and 7$0^{\circ}C$. The pH of yoghurt was not changed when the yoghurt was heated at 7$0^{\circ}C$, but at 55$^{\circ}C$ it decreased slightly. The stability of $\beta$-galactosidase was not affected markedly by heat treatment at 55$^{\circ}C$, but was rapidly inactivated at 7$0^{\circ}C$. The heat treatment of yoghurt at 55$^{\circ}C$ had the halb of viable cell in 1 hour, but the heat treatment at 7$0^{\circ}C$ had considerable effect on viable cell in 5 minutes.

• 미생물학회지
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• 제27권3호
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• pp.188-193
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• 1989

Gene for lactose catabolism in Lactobacillus casei SW-M1 was encoded by a 60Kb metabolic plasmid. A derivative of only 10kb, pPlac 15 of recombinant plasmid, was constructed by introducing into pBR322 and was cloned into E. coli using restriction endonuclease Pst I. A 10kb insery DNA in plasmid pBR322 was identified as a gene encoded phospho-$\beta$-galactosidase by the determination of enzyme activity. Phospho-$\beta$-galactosidase was apparently expressed in E. coli. The enzyme activities of cell-free extract from transformant E. coli HB101 carrying pPLac 15 DNA were not different from that of L. casei as a donor strain on the basis of enzyme properites. However, specific activity of phospho-$\beta$-galactosidase in the cloned strain with Lac $Y^{-}$ phenotype of E. coli HB101 was lower than that in L. casei strain.

• 한국식품영양과학회지
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• 제31권1호
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• pp.50-56
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• 2002

달팽이 내장을 마쇄, 추출, 염석 및 투석 후 얻은 조효소액을 두 번의 이온교환 크로마토그래피 및 두 번의 겔여과 크로마토그래피를 거쳐 최종적으로 얻은 $\beta$-galactosidase의 비활성도는 18.8 units/mg protein이었고, 정제도는 31.3%배, 수율은 20.8%이었다. $\beta$-Gallactosidase의 분자량을 측정하기 위해 겔 여과와 전기영동을 실시한 결과, native molecular weight가 약 144,000으로, SDS-PAGE 결과, 약 72,000으로 나타나 이 효소는 동일한 polypeptide로 구성된 dime로 추측되었으며, 등전점은 pI 4.1이었다. $\beta$-Galactosidase의 최적 pH와 온도는 각각 pH 3.0과 6$0^{\circ}C$로 측정되었으며, pH 2.0~8.0에서 80%이상의 효소 활성을 나타내었고, 온도 30~5$0^{\circ}C$에서 안정되었다. 모든 금속이온과 fructose, glucose, galactose, maltose 및 xylose는 $\beta$-galactosidase의 저해제로 작용하였다.

• Journal of Microbiology and Biotechnology
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• 제9권2호
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• pp.201-205
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• 1999

The effects of growth temperature and a carbon source on the expression of $\beta$-galactosidase gene of Lactococcus lactis ssp. lactis ATCC 7962 (L. lactis 7962) were investigated. At $25^{\circ}C$, L. lactis 7962 had a higher $\beta$-galactosidase activity than cells grown at $30^{\circ}C$ or $37^{\circ}C$, although cells grew most quickly at $37^{\circ}C$ The highest $\beta$-galactosidase activity was observed in cells grown in M17 with lactose (l %) followed by cells grown in a galactose (1 %) medium. L. lactis 7962 exhibited the minimum $\beta$-galactosidase activity in glucose media, indicating catabolite repression. When the cellular levels of $\beta$-galactosidase mRNA were examined using slot blot hybridization, no significant differences were observed between cells grown at $25^{\circ}C$ and cells at $30^{\circ}C$ or $37^{\circ}C$ in the same media. This suggests that the quantity of $\beta$-galactosidase mRNA may not be the reason for the higher $\beta$-galactosidase activities of L. lactis 7962 at $25^{\circ}C$ The level of ccpA (Catabolite Control Protein) transcript remained almost constant during the exponential growth phase irrespective of a carbon sourse.

• KSBB Journal
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• 제11권4호
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• pp.398-404
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• 1996

전세포 효소 고정화 캡슐을 제조하기 위하여 Eschericia coli를 calcium alginate 캡슐내부에 접종하고 배양하였다. E. coli의 캡슐내부 건조중량이 1OOg/L에 달하였다. 생산배지에서 배양하는 동안 캡슐내부에 축적되는 미생물의 양이 많을수록 캡슐 내부에 축적되는 $\beta$galactosidase의 활성도 높았다. 생산배지에 금속이온 $Zn^{+2}를 2{\times}10^{-4} M $ 첨가함으로써 캡슐내부에 축척되는 ${\beta}$-galactosidase의 활성 을 25% 증가시킬 수 있었다. 캡슐제조시 해바라기유를 부피비로 2% 첨가함으로써 캡슐내부에 축적되 는 ${\beta}$-galactosidase의 활성을 10% 증가시킬 수 었었다. 부피산소전달계수, $k_La가 2.55h^- $ 안 플라스크 대신 $k_La가 82h^- $인 concentric air lift reactor 내에서 고정화 E. coli를 배양호농로써 캡슐내부의 전세포${\beta}$-galactosidase의 활성을 86% 증가시킬 수 있었다.

• 자연과학논문집
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• 제5권1호
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• pp.37-45
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• 1992

Neisseria lactamica 2118 의 $\beta$-galactosidase 유전자를 Southern Hybridization 과 colony hybridization을 통하여 Escherichia coli MC 1061에 클로닝 시켰다. $\beta$-Galactosidase 유전자를 함유하는 6.5 Kb EcoR I 단편과 7.2 Kb BamH I 단편들을 pMC 1871의 lac Z 유전자를 probe로 한 Southern hybridization으로 얻고 이들을 pBR 322에 삽입한후 Escherichia coli MC 1061에 형질전환 시키고 이들 형질전환체들을 동일 probe로 colony hybridization 시켜 최종적으로 3주의 $\beta$-galactosidase positive clone들을 얻었다. 이들의 재조합 plasmid에는 Neisseria lactomica 2118 염색체 DNA의 약 7.2Kb BamH I 단편이 삽입되어 있음을 확인 하였고 probe와 상동성이 가장 강한것으로 추정되는 pNL 24에 대한 제한효소지도를 작성 하였다.

• 한국미생물·생명공학회지
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• 제40권1호
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• pp.17-22
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• 2012

가정에서 제조된 청국장으로부터 lactose를 glucose와 galactose로 가수분해하는 ${\beta}$-galactosidase의 생산균을 분리하였다. 분리균 YB-1105는 형태적 특성, 생화학적 성질 및 16S rRNA 유전자 염기서열에 근거하여 Bacillus licheniformis로 확인되었다. B. licheniformis YB-1105의 배양상등액과 균체파쇄액에서 모두 ${\beta}$-galactosidase 활성이 관찰되었으며 이들은 모두 pH 6.5와 $50^{\circ}C$의 반응조건에서 paranitrophenyl-${\beta}$-D-galactopyranoside의 가수분해 활성이 최대로 나타났다. 그러나 균체파쇄상등액에 비해 배양상등액의 ${\beta}$-galactosidase 활성은 산성 pH와 고온에서 크게 영향을 받았다. 한편 두 분획의 가수분해 활성은 낮은 농도의 galactose에 의해도 급격하게 저해되었으나, glucose와 mannose는 고농도에 의해서는 약하게 저해를 받는 것으로 확인되었다.

• Journal of Microbiology and Biotechnology
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• 제32권6호
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• pp.749-760
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• 2022

α-Galactosidase is a debranching enzyme widely used in the food, feed, paper, and pharmaceuticals industries and plays an important role in hemicellulose degradation. Here, T26, an aerobic bacterial strain with thermostable α-galactosidase activity, was isolated from laboratory-preserved lignocellulolytic microbial consortium TMC7, and identified as Parageobacillus thermoglucosidasius. The α-galactosidase, called T26GAL and derived from the T26 culture supernatant, exhibited a maximum enzyme activity of 0.4976 IU/ml when cultured at 60℃ and 180 rpm for 2 days. Bioinformatics analysis revealed that the α-galactosidase T26GAL belongs to the GH36 family. Subsequently, the pET-26 vector was used for the heterologous expression of the T26 α-galactosidase gene in Escherichia coli BL21 (DE3). The optimum pH for α-galactosidase T26GAL was determined to be 8.0, while the optimum temperature was 60℃. In addition, T26GAL demonstrated a remarkable thermostability with more than 93% enzyme activity, even at a high temperature of 90℃. Furthermore, Ca²⁺ and Mg²⁺ promoted the activity of T26GAL while Zn²⁺ and Cu²⁺ inhibited it. The substrate specificity studies revealed that T26GAL efficiently degraded raffinose, stachyose, and guar gum, but not locust bean gum. This study thus facilitated the discovery of an effective heat-resistant α-galactosidase with potent industrial application. Meanwhile, as part of our research on lignocellulose degradation by a microbial consortium, the present work provides an important basis for encouraging further investigation into this enzyme complex.

• Asian-Australasian Journal of Animal Sciences
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• 제27권5호
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• pp.700-705
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• 2014

A 12-week feeding trial was conducted with 87 g rainbow trout to evaluate the effects on growth performances, feed efficiency and nutrient digestibility of adding ${\beta}$-mannanase and ${\alpha}$-galactosidase enzymes, solely or in combination. Seven diets were prepared by adding ${\beta}$-mannanase, ${\alpha}$-galactosidase and mixed enzyme at two different levels (1 g/kg and 2 g/kg) to control diet (without enzyme) including soybean meal. Mixed enzymes (1 g/kg, 2 g/kg) were prepared by adding ${\beta}$-mannanase and ${\alpha}$-galactosidase at the same doses (0.5+0.5 g/kg and 1+1 g/kg). At the end of the experiment, addition of ${\beta}$-mannanase, ${\alpha}$-galactosidase and mixed enzyme to diet containing 44% soybean meal had no significant effects on growth performance and gain:feed (p>0.05). In addition, adding ${\beta}$-mannanase, ${\alpha}$-galactosidase and mixed enzyme in different rations to trout diets had no affect on nutrient digestibility and body composition (p>0.05).

• 한국수산과학회지
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• 제47권5호
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• pp.516-521
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• 2014

A bacterium producing ${\alpha}$-galactosidase (${\alpha}$-$\small{D}$-galactoside galactohydrolase, EC 3.2.1.22) was isolated. The isolate, KM-1 was identified as Bacillus coagulans based on its 16S rRNA sequence, morphology, and biochemical properties. ${\alpha}$-Galactosidase activity was detected the culture supernatant of B. coagulans KM-1. The bacterium showed the maximum activity for hydrolyzing para-nitrophenyl-${\alpha}$-$\small{D}$-galactopyranoside (pNP-${\alpha}Gal$) at pH 6.0 and $50^{\circ}C$. It hydrolyzed oligomeric substrates such as melibiose, raffinose, and stachyose liberating a galactose residue, indicating that the B. coagulans KM-1 ${\alpha}$-galactosidase hydrolyzed ${\alpha}$-1,6 linkage. The results suggest that the decreased stachyose and raffinose contents in fermented soybean meal are due to the ${\alpha}$-galactosidase activity.