• Journal of Microbiology and Biotechnology
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• v.25 no.4
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• pp.469-478
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• 2015

In spite of the reported probiotic effects, Bifidobacterium bifidum BGN4 (BGN4) showed no βglucosidase activity and failed to biotransform isoflavone glucosides into the more bioactive aglycones during soy milk fermentation. To develop an isoflavone-biotransforming BGN4, we constructed the recombinant B. bifidum BGN4 strain (B919G) by cloning the structural β-glucosidase gene from B. lactis AD011 (AD011) using the expression vector with the constitutively active promoter 919 from BGN4. As a result, B919G highly expressed β-glucosidase and showed higher β-glucosidase activity and heat stability than the source strain of the β-glucosidase gene, AD011. The biotransformation of daidzin and genistin compounds using the crude enzyme extract from B919G was completed within 4 h, and the bioconversion of daidzin and genistin in soy milk during fermentation with B919G also occurred within 6 h, which was much faster and higher than with AD011. The incorporation of this β-glucosidase-producing Bifidobacterium strain in soy milk could lead to the production of fermented soy milk with an elevated amount of bioavailable forms of isoflavones as well as to the indigenous probiotic effects of the Bifidobacterium strain.

• Food Engineering Progress
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• v.15 no.3
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• pp.214-220
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• 2011

$\beta$-Glucosidase enzyme reaction under high hydrostatic pressure was investigated in terms of physical chemistry. A model substrate (p-nitrophenyl-${\beta}$-D-glucopyranoside(pNPG)) was used, and the pressure effects on the enzymatic hydrolysis (pNPG${\rightarrow}$pNP) at 25 MPa, 50 MPa, 75 MPa, and 100 MPa were analyzed. Two parts of the reaction such as kinetic and equilibrium stages were considered for mathematical modelling, and their physicochemical parameters such as forward and inverse reaction constants, equilibrium constant, volume change by pressure, etc. were mathematically modeled. The product concentration increased with pressure, and the two stages of reaction were observed. Prediction models were derived to numerically compute the product concentrations according to reaction time over kinetic to equilibrium stages under high pressure condition. Conclusively, the $\beta$-Glucosidase enzyme reaction could be activated by pressurization within 100 MPa, and the developed models were very successful in their prediction.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.251-261
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• 2010

Cellulase from Formiptosis pinicola KMJ812 is an efficient cellulose degradation enzyme complex, especially with a high ${\beta}$-glucosidase activity. In this study, the change in enzymatic characteristics by immobilization and the reduction of immobilized enzyme activity by repeated usages were evaluated using cellulases from F. pinicola KMJ812. Among tested four resins, Duolite A568 resin had the best enzyme activity yield with 61.7% cellulase activity and 64.4% ${\beta}$- glucosidase activity during the cellulase immobilization. The best reaction temperature was $55^{\circ}C$ for both cellulase and ${\beta}$-glucosidase activities which were higher than the unimmobilized soluble cellulases. The best reaction pH was 4.0 for cellulase activity which was a little more basic than a soluble form and 4.5 for ${\beta}$-glucosidase activity. The immobilized cellulase activity was remained 98% of the beginning activity after 72 h incubation at $50^{\circ}C$ and 50% of the beginning activity after eight times usage at $50^{\circ}C$.

• Korean Journal of Medicinal Crop Science
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• v.21 no.4
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• pp.301-305
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• 2013

This study was performed to select adequate plant materials for developing a natural ${\alpha}$-glucosidase inhibitor by analyzing ${\alpha}$-glucosidase inhibition activity in fronds and rhizomes of three Dryopteridaceae species: Cyrtomium fortunei, Polystichum polyblepharum, and P. lepidocaulon. The highest ${\alpha}$-glucosidase inhibitor obtained from frond of P. lepidocaulon ($4.16{\mu}g{\cdot}mL^{-1}$), and rhizome of C. fortunei ($1.84{\mu}g{\cdot}mL^{-1}$), showed much higher inhibition activity than acarbose ($1413.70{\mu}g{\cdot}mL^{-1}$). The biomass required to inhibit ${\alpha}$-glucosidase by 50% was 0.04 ~ 0.35mg for frond and 0.03 ~ 0.10mg for rhizome, and P. lepidocaulon required the least amount of fronds and P. lepidocaulon the least rhizomes. In frond, ${\alpha}$-glucosidase inhibition activity was the highest in water fraction of C. fortunei ($20.2{\mu}g{\cdot}mL^{-1}$), and n-butanol fraction of P. lepidocaulon ($9.33{\mu}g{\cdot}mL^{-1}$) and P. polyblepharum ($5.10{\mu}g{\cdot}mL^{-1}$). In rhizome, it was the highest in n-butanol fractions of C. fortunei ($19.76{\mu}g{\cdot}mL^{-1}$) and P. polyblepharum ($4.47{\mu}g{\cdot}mL^{-1}$), and ethylacetate fraction of P. lepidocaulon ($5.46{\mu}g{\cdot}mL^{-1}$). The frond biomass required for 50% ${\alpha}$-glucosidase inhibition was the lowest in the water fraction of C. fortunei (1.43mg), and n-butanol fractions of P. lepidocaulon (1.10mg) and P. polyblepharum (0.66mg). The required biomass of rhizome was the lowest in the water fraction of C. fortunei (1.59mg), and n-hexane fractions of P. lepidocaulon (0.04mg) and P. polyblepharum (0.15mg). The result of this study suggested that the three Dryopteridaceae species had high ${\alpha}$-glucosidase inhibition activity with small biomass, which might have high value as materials for economical anti-diabetic medication.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.12-17
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• 2000

For the enzymatic production of $2-O-{\alpha}-D-glucopyranosyl-L-ascorbic$ acid (AA-2G) from ascorbic acid, rice seed was used as the source of ${\alpha}-glucosidase$ having transglucosylation activity. Among six rice varieties, cultivated in Korea, ${\alpha}-glucosidase$ activity of Oryza savita L. cv. Ilpumbyeo was the highest with 125.03 unit/ml and it had maximum specific activity with 8.52 unit/mg protein when rice seeds were grown for 3 days after germination. For the production of AA-2G using crude extract of O. savita L. cv. Ilpumbyeo, maltose was most effective glucose donor. The optimum concentration of maltose and ascorbic acid were 125 mM and 175 mM, respectively. The optimum concentration of ${\alpha}-glucosidase$ was 100 unit. The most effective buffer was 100 mM sodium citrate. The optimum pH and temperature were 5.0 and $60^{\circ}C$, respectively. Under the optimum condition, $108.43\;{\mu}M/unit$ of AA-2G was produced from ascorbic acid after 35 minutes of reaction, which corresponds to 6.2% of conversion ratio based on the amount of ascorbic acid used.

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1148-1157
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• 2006

A hyperthermophilic bacterium Thernotoga maritima produced thermostable ${\beta}-glucosidase$. The gene encoding ${\beta}-glucosidase$ from T. maritima MSB8 was cloned and expressed in Escherichia coli. The en-zyme (BgIB) hydrolyzed ${\beta}-glucosidase$ linkages between glucose and alkyl, aryl of saccharide groups such as salicin, arbutin, and $_pNPG$. The insert DNA contained ORF with 2,166 bp encodes a 721 amino acids (calculated molecular mass of 80,964 and pl of 4.93). The amino a.id sequence of BglB showed the similarity to family 3 glycosyl hydrolases. The molecular weight of the enzyme was estimated to be approximately 81kDa by MUG-nondenaturing PAGE (4-methylumbelliferyl 13-D-glucoside-nondenaturing polyacrylamide gel electophoresis) and SDS-PACE. The ${\beta}-glucosidase$ exhibited maximal activity at pH 7.0 and $80^{\circ}C$. By exchanging two possible residues (Glu-232 and Asp-242) to Ala by site-directed mutagenesis method, it was found that these were essential for enzymatic activity.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.4
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• pp.398-407
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• 2020

The inhibitory effect on α-glucosidase, a marker of postprandial hyperglycemia, and angiotensinconverting enzyme (ACE), a marker of hypertension, was analyzed using non-fermented green tea and three different types of fermented tea, which are popular beverages in modern life. Green tea was mixed with trace amounts of vanadate (50 ㎍/mL), which has insulin-mimetic effects, to investigate the synergistic effect of vanadate on the inhibition of α-glucosidase. The concentration of epigallocatechin gallate (EGCG) and caffeine was also checked. The extracts of green tea and fermented teas showed clear inhibition on α-glucosidase, which caused a decrease in the postprandial glucose levels. The inhibitory effect was most prominent in the 20% fermented tea. Trace amounts of vanadate (50 ㎍/mL)-mixed green tea extract had twice the inhibitory effect on α-glucosidase than the pure tea extract. All teas showed inhibitory effects on ACE. Among those, the effect was most prominent in green tea, which had higher concentrations of EGCG. In contrast, the postprandial glucose-lowering effect and ACE inhibition of the fermented teas, which have a lower level of EGCG, was attributed to some other different functional substances.

• Journal of the Korean Applied Science and Technology
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• v.40 no.5
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• pp.1126-1135
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• 2023

Nine microbial strains were isolated from the byproduct of ginseng processing and field of ginseng cultivation. Two strains among them were confirmed. Phylogenetic analysis of these 𝛽-Glucosidase strains confirmed that strain GYP-1 belongs to the Rhodotorula and strain GYP-3-3 belong to genus Brachybacterium. Rhodotorula sp. GYP-1 was finally selected due to its high biomass production. The 𝛽-Glucosidase activity of Rhodotorula sp. GPY-1 was assessed at 30 ℃, and Higher than 70% of the enzyme activity was maintained at the temperature range of 20-40℃. Although the optimum pH for the highest enzyme activity was pH 5.0, the enzyme was stable throughout the pH range of 5.0-8.0. In addition, Rhodotorula sp. demonstrated antifungal activity against the ginseng root rot disease caused by Botrytis.

• KSBB Journal
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• v.11 no.3
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• pp.347-352
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• 1996

The enzyme deactivation in a membrane recycling system for the simultaneous saccharification and fermentation(SSF) was studied under various temperature and pressure. The optimum molecular weight cut off(MWCO) of the ultrafiltration membrane for recycling cellulase and ${\beta}$-glucosidase was 50,000. When the cellulase was recycled continuously through the membrane system, it was not deactivated. But the activity of ${\beta}$-glucosidase was decreased with an increase in operating temperature and transmembrane pressure. After 720 minutes at $42^{\circ}C$ and 24.8 psig , the activity of ${\beta}$-glucosidase was reduced by 35% of the initial activity. Such tendencies could be well explained by the results of highly induced shear at the fiber surface of membrane when temperature and transmembrane pressure became higher.

• Preventive Nutrition and Food Science
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• v.17 no.4
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• pp.239-244
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• 2012

This study investigated the hypoglycemic effect of the Padina arborescens extract in STZ-induced diabetic mice. Freeze-dried Padina arborescens were extracted with 80% methanol and concentrated for use in this study. The hypoglycemic effect was determined by inhibitory activities against ${\alpha}$-glucosidase and ${\alpha}$-amylase as well as the alleviation of postprandial blood glucose level. Padina arborescens extracts showed higher inhibitory activities than acarbose, a positive control against ${\alpha}$-glucosidase and ${\alpha}$-amylase. The $IC_{50}$ values of Padina arborescens extracts against ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.26 and 0.23 mg/mL, respectively, which evidenced as more effective than observed with acarbose. The increase of postprandial blood glucose levels were significantly suppressed in the Padina arborescens extract administered group than the control group in the streptozotocin induced diabetic mice. Furthermore, the area under the curve (AUC) was significantly lowered via Padina arborescens extract administration in diabetic mice (p 0.05). These results indicated that the Padina arborescens extract might be used as an inhibitor of ${\alpha}$-glucosidase and ${\alpha}$-amylase and delay absorption of dietary carbohydrates.