• Journal of Microbiology and Biotechnology
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• 제8권5호
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• pp.441-448
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• 1998

A cellobiose-utilizing recombinant yeast having $\beta$-glucosidase activity was developed for ethanol production from a mixture of glucose and cellobiose. Using $\delta$-sequences of Tyl transposon of yeast as target sites for homologous recombination, a heterologous gene of $\beta$-glucosidase was integrated into the chromosome of Saccharomyces cerevisiae. The $\delta$-integrated recombinant yeast, Saccharomyces cerevisiae L2612 (Pb-BGL), showed perfect mitotic stability even in nonselective media and showed ca. 1.5 fold higher $\beta$-glucosidase activity than the recombinant yeast harboring the $2\mu$-based plasmid vector system. A mathematical model was developed to describe the $\beta$-glucosidase formation and ethanol production from the Saccharomyces cerevisiae L2612 ($p\delta-BGL$). The model newly described that the heterologous $\beta$-glucosidase production mediated by ADH1 promoter is regulated by glucose and repressed by ethanol.

• 한국식품과학회지
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• 제37권3호
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• pp.504-507
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• 2005

Trichoderma reesei KCTC 6952는 고분자 섬유소인 cellulose를 분해하는데 관여하는 3종류의 효소로 구성된 cellulase system을 보유하고 있다. 그 중 ${\beta}$-glucosidase는 glucose를 함유한 glycoside 유도체들로부터 glucose를 효율적으로 유리할 수 있는 것으로 알려져 있다. 본 연구에서는 변형된 Mandels의 배지를 사용하여 T. reesei KCTC 6952를 배양하면서 배지로 분비된 ${\beta}$-glucosidase를 조효소액으로 회수하여 조효소액내의 ${\beta}$-glucosidase 활성을 측정하고, 또한 효소활성이 온도와 pH에 대하여 어느 정도 안정한 지를 조사하였다. 그 결과 배양 4일째에 ${\beta}$-glucosidase의 효소활성이 최고(1.33 unit/mL)에 도달하였으며, 조효소액내의 ${\beta}$-glucosidase의 최적 반응 조건은 pH 5과 $70^{\circ}C$에서 10분간 반응하는 것이었으며, 그리고 효소의 안정성을 실험한 결과에 의하면 pH 4-5의 범위에서, $50^{\circ}C$ 이하에서는 안정적이었다. 그러므로 결론적으로 본 연구를 위하여 선택된 ${\beta}$-glucosidase 조효소액은 비교적 높은 온도와 넓은 pH범위에서 촉매반응을 일으킬 수 있었다.

• 미생물학회지
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• 제27권1호
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• pp.35-42
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• 1989

The mode of transglycosylation reaction observed during the action of low-molecular-weigh $\beta$-D-glucosidase ($\beta$-D-glucoside glucohydrolase, EC3.2.1.21) purified from Trichoderma koningii ATCC 26113 was investigated using $^{1}H$-NMR spectroscopy. The enzyme was purified by the series of procedures including ammonium sulfate precipitation, and fractionations by column chromatographies on Bio-Gel P-150, DEAE-Sephadex A-50, and SP-Sephadex C-50. The final purification was performed by the band eluation after preparative polyacrylamide gel electrophoresis. The enzyme showed its molecular size of 78,000 through the analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and its isoelectric point of 5.80 through the analysis of analytical isoelectric focusing. The H-1 proton resonances were analyzed. After the reaction of the enzyme with cellobiose, the reaction products were separated by high performance liquid chromatography using refractive index detector. H-1 resonances of the products were consisted with those of gentiobiose [$\beta$-D-glucopyranosyl--(1,6)-D-glucopyranose], and cellotriose [$\beta$-D glucopyranosyl-(1,4)-$\beta$-D-glucopyranosyl]-(1,4)-D-glucopyranose] with minor resonances of sophorose [$\beta$-D-glucopyranosyl-(1,2)-D-glucopyranose], respectively.

• Journal of Microbiology and Biotechnology
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• 제12권1호
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• pp.8-13
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• 2002

The isoflavone glycosides are hydrolyzed by ${\beta}$-glucosidase from gut microbes to the bioactive aglycones. However, the specific bacteria from the human intestinal tract that are involved in the metabolism of these compounds are not known. This study was undertaken to develop a fermented soymilk which converts isoflavones to the more bioactive aglycones form using a Bifidobacterium strain. The ${\beta}$-glucosidase activity of 15 Bifidobacterium strains were measured during cell growth. Among them, Bifidobacterium sp. Int-57 was selected for this study, because it has the highest ${\beta}$-glucosidase activity. Growth, acid development, ${\beta}$-glucosidase activity, and the hydrolysis of daidzin and genistin were investigated in four soymilks inoculated with Bifidobacterium sp. Int-57. After 12 h of fermentation, the counts of viable Bifidobacterium sp. Int-57 in all the soymilks reached a level of more than $10^8$ cfu/ml, which was then maintained. The pH of soymilks started to decrease rapidly after 6 h of fermentation and leveled off after 18 h. The titratable acidity of BL# 1 soymilk, BL#2 soymilk, and JP#l soymilk increased from 0.18 to 1.21, 1.15, and $1.08\%$ over the fermentation period, respectively. After 24 h of fermentation, the $\beta$-glucosidase activity in BL#1 soymilk, BL#2 soymilk, JP#l soymilk, and JP#2 soymilk increased to 59.528, 40.643, 70.844, and 56.962 mU/ml, respectively. The isoflavone glycosides, daidzin and genistin, in soymilks were hydrolyzed completely in the relatively short fermentation time of 18 h. These results show that Bifidobacterium sp. Int-57 can be used as a potential starter culture for developing fermented soymilk which has completely hydrolyzed isoflavone glycosides.

• KSBB Journal
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• 제15권1호
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• pp.9-13
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• 2000

Cellulose 분해에 관련된 $\beta$-Glucosidase 효소 활성의 특성 파악을 위하여 송이균사(Tricholoma matsutake DGUM 26001)의 액체 배양시 세포외로 분비되는 $\beta$-Glucosidase 효소를 부분정제하여 그 특성을 조사하였다. 효소 활성에 미치는 적정 온도는 55-$70^{\circ}C$이었고 최적 온도는 $65^{\circ}C$이었다. 적정 효소활성에 영향을 주는 적정 pH는 3.0-5.0 범위였으며 최적 pH는 4.0이었다. Salicin을 기질로 최적 조건하에서 $\beta$-Glucosidase 효소의 비활성도는 18.7 unit/mg protein이었다. 열안정성은 $60^{\circ}C$이하의 온도에 60분간 열처리시 약 90%이상의 효소활성을 유지하였다. $Fe^{++}$이온은 효소활성을 촉진하였으나, $Hg^{++}$ 및 $Cu^{++}$이온은 효소활성을 매우 억제하였다. Salicin에 대한 효소활성을 100으로 하였을 때, cellobiose는 48.6%의 상대적 효소활성을 나타내었으며, cellobiose에 대한 Km값 및 Vmax값은 각각 0.12mM과 0.02umol/min었다.

• Journal of the Korean Wood Science and Technology
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• 제35권5호
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• pp.100-108
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• 2007

$\beta$-Glucosidase from Laetiporus sulphureus among the enzymes related to lignocellulosic biomass degradation to sugars for using alternative bioethanol production was characterized. The highest activity of $\beta$-glucosidase was obtained on cellobiose at shaking culture. For the characterization and purification of $\beta$-glucosidase culture solution was concentrated and then purified by FPLC using ion exchange and size exclusion column. According to the results of SDS-PAGE, native PAGE and microfluidic system of purified enzyme, protein band was observed at about 132 kDa. Optimal pH and temperature of purified $\beta$-glucosi-dase were 5.0 and $60^{\circ}C$, respectively. In the kinetic properties of $\beta$-glucosidase on various substrates such as sophorose, gentiobiose and cellobiose, $K_m$ was 0.81, 1.07 and 1.70 mM, respectively.

• Journal of Ginseng Research
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• 제23권1호
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• pp.50-54
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• 1999

In this paper, the saponin enzymatic hydrolysis of ginsenoside Rg3 was studied. The $ginsenoside-{\beta}-glucosidase$ from FFCDL-48 strain mainly hydrolyzed the ginsenoside Rg3 to Rh2, the enzyme from FFCDL-00 strain hydrolyzed Rg3 to the mixture of Rh2 and protopanaxadiol (aglycon). The $ginsenoside-{\beta}-glucosidase$ from FFCDL-48 strain was purified with a column of DEAE-Cellulose to one spot in the SDS polyacrylamide gel electrophoresis. During the purification, the enzyme specific acitvity was increased about 10 times. The purified $ginsenoside-{\beta}-glucosidase$ can hydrolyze the Rg3 to Rh2, but do not hydrolyze the $p-nitrophenyl-{\beta}-glucoside$ which is a substrate of original exocellulase such as ${\beta}-glucosidase$ of cellulose. The molecular weight of $ginsenoside-{\beta}-glucosidase$ was 34,000, the optimal temperature of enzyme reaction was $50^{\circ}C,$ and the optimal pH was 5.0.

• 약학회지
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• 제37권2호
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• pp.187-192
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• 1993

Approximately 1% of intestinal bacteria of human and rats was alkalotolerant. Among these bacteria of human, bacteria producing $\beta$-glucosidase, $\beta$-glucuronidase and sulfotransferase were 40%, 4% and 0%, respectively. Among alkalotolerant intestinal bacteria of rats, bacteria producing, these enzymes were 70%, 8% and 0%, respectively. $\beta$-Glucosidase and $\beta$-glucuronidase of alkalotolerant intestinal bacteria of human and rat were induced by the medium of high pH: these enzymes activities were increased by elevating pH of the medium, but the growths were not changed. The enzyme activities at the medium of pH 7 were about ten-fold higher than those at the medium of pH 6.

• Food Science and Biotechnology
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• 제17권5호
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• pp.1021-1024
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• 2008

Genistein, one of the isoflavones in doenjang, is generally known to prevent various cancers, osteoporosis, climacterium, and menopause symptoms, and has better bioavailability and healthful physiological effects than its glucoside, genistin. In both traditional and commercial doenjangs, genistein content ranged from 370 to 1,510 mg/kg, however, significant amounts of genistin also existed at the level of 190 to 350 mg/kg. After treating with corn $\beta$-glucosidase, over 84% of genistin in doenjang was converted to genistein. However, physiochemical characteristics such as pH, viscosity, 2-thiobarbituric acid (TBA) value, and color were not changed significantly after corn $\beta$-glucosidase treatments. Therefore, this study shows that the improved doenjang with the increased genistein content can be produced using corn $\beta$-glucosidase.

• KSBB Journal
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• 제6권2호
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• pp.147-156
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• 1991

Diazotized chitin (CHITN) was synthesized reacting with NaN3 and HCl to alkaline hydrolyzed chitin for the support of immobilized enzyme. Immobilized $\beta$-glucosidase on diazotized chitin(CHITN-Gase) was produced reacting with glutaraldehyds as bifunctional reagent. CHITN-Gase activities were determined reacting with p-nitrophenol-$\beta$-D-glucopyranoside in plug flow reactor as a reference. Optimum temperature, optimum pH, reaction constant and deactivation rate were determined with variation of flow rate and H/D. The particle size of immobilized enzyme in the best was, 35 mesh (CHITN35-Gase). The optimum conditions of immobilized enzyme were $70^{\circ}C$ in temperature and 5.0 in pH. Diameter and flow rate of plug flow reactor in the best was 8.5mm in diameter and 0.8ml/min in flow rate. Reaction constant was mainly influenced by electrostatic force. The best glucose hydrolizing activities of CHITN3 5-Gase was 3.34$\times$10-5 M/1. while that of native-$\beta$-glucosidase was 2.44$\times$10-5 M/1.