• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1649-1656
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• 2017

In simultaneous saccharification and fermentation (SSF) for production of cellulosic biofuels, engineered Saccharomyces cerevisiae capable of fermenting cellobiose has provided several benefits, such as lower enzyme costs and faster fermentation rate compared with wild-type S. cerevisiae fermenting glucose. In this study, the effects of an alternative intracellular cellobiose utilization pathway-a phosphorolytic pathway based on a mutant cellodextrin transporter (CDT-1 (F213L)) and cellobiose phosphorylase (SdCBP)-was investigated by comparing with a hydrolytic pathway based on the same transporter and an intracellular ${\beta}$-glucosidase (GH1-1) for their SSF performances under various conditions. Whereas the phosphorolytic and hydrolytic cellobiose-fermenting S. cerevisiae strains performed similarly under the anoxic SSF conditions, the hydrolytic S. cerevisiae performed slightly better than the phosphorolytic S. cerevisiae under the microaerobic SSF conditions. Nonetheless, the phosphorolytic S. cerevisiae expressing the mutant CDT-1 showed better ethanol production than the glucose-fermenting S. cerevisiae with an extracellular ${\beta}$-glucosidase, regardless of SSF conditions. These results clearly prove that introduction of the intracellular cellobiose metabolic pathway into yeast can be effective on cellulosic ethanol production in SSF. They also demonstrate that enhancement of cellobiose transport activity in engineered yeast is the most important factor affecting the efficiency of SSF of cellulose.

• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1559-1565
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• 2017

Naturally occurring ginsenoside F1 (20-O-${\beta}$-$\text\tiny{D}$-glucopyranosyl-20(S)-protopanaxatriol) is rare. Here, we produced gram-scale quantities of ginsenoside F1 from a crude protopanaxatriol saponin mixture comprised mainly of Re and Rg1 through enzyme-mediated biotransformation using recombinant ${\beta}$-glucosidase (BgpA) cloned from a soil bacterium, Terrabacter ginsenosidimutans Gsoil $3082^T$. In a systematic step-by-step process, the concentrations of substrate, enzyme, and NaCl were determined for maximal production of F1. At an optimized NaCl concentration of 200 mM, the protopanaxatriol saponin mixture (25 mg/ml) was incubated with recombinant BgpA (20 mg/ml) for 3 days in a 2.4 L reaction. Following octadecylsilyl silica gel column chromatography, 9.6 g of F1 was obtained from 60 g of substrate mixture at 95% purity, as assessed by chromatography. These results represent the first report of gram-scale F1 production via recombinant enzyme-mediated biotransformation.

• KSBB Journal
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• v.6 no.2
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• pp.167-174
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• 1991

Enzymatic cellulose hydrolysis depends on the several factors such as the structural features (CrI, particle size and surface area, etc.), the nature of cellulase enzyme system, the inhibitory effects of products, and enzyme deactivation. At the presence of products on the initial hydro- lysis rate of cellulose, cellobiose has more severe inhibitory effect than glucose. Othewise, the inhibition effect of products for adsorbed enzyme is related to the glucose and cellobiose conentration hyperbolically. Enzyme deactivation of FPA and ${\beta}-glucosidase$ were expressed by exponential decay profile.

• Korean Journal of Ecology and Environment
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• v.35 no.4 s.100
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• pp.266-272
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• 2002

For analyzing function of a microbial ecosystem which was created under the artificial vegetation island (AVI) installed at Lake Paldang, zooplankton and bacterial numbers and exoenzyme activities (${\beta}$-glucosidase and phosphatase) were measured biweekly from 3 November 2()()1 to 20 April 2002 at AVI site and control site. Under the AVI, the water quality was worse than control site in term of comparing the environmental parameters. But, zooplankton number of AVI site was 25 times higher than that of control site. Respiratory active bacterial numbers were 3-8 times higher at AVI site. In addition, enzymatic activities were higher at AVI site than those of control site. These results suggest that the zooplankton-phytoplankton-bacteria relationships are closely coupled with each other and organic materials are eliminated by respiration of zooplankton and bacterial activities.

• KSBB Journal
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• v.27 no.6
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• pp.361-366
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• 2012

We investigated the anti-diabetic activity and enzymatic activity of 24 commercial doenjang samples certified for traditional foods. Twenty four doenjang samples showed the wide ranges in enzymatic activities (protease activities 0-50.45 unit/g, ${\alpha}$-amylase activities 0-675.9 unit/g, ${\beta}$-amylase 13.6-308.6 unit/g), and there were no difference in enzymatic activity by the producing region. To evaluate the potential anti-diabetic activity of 24 doenjang samples, we examined the effect of doenjang methanol extract (DME) on 2-[n-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amyno]-2-deoxy-d-glucose (2-NBDG) uptake. Ten samples among 24 samples significantly stimulated the uptake of 2-NBDG. When the cells were treated with DME at 400 ug/mL, No. 17 and 23 specially stimulated 2-NBDG uptake by 1.23-fold and 1.25-fold, respectively, compared with untreated control cell. And there were no cytotoxicity in the C2C12 cells treated with DME at concentration of 500 ug/mL. Among 24 samples, No. 6, 7, 12, 21 and 24 showed the ${\alpha}$-glucosidase inhibitor activity at concentration of 10 mg/mL; however, they were less effective than acarbose which is a commercial ${\alpha}$-glucosidase inhibitor.

• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.20-27
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• 2001

An effective method for production of glucose was developed using enzymatic hydrolysis of Suwon poplar by the cellulase. Enzymatic hydrolysis of wood is the reaction to produce glucose from wood using enzyme which derives from microorganism. Glucose can be transferred easily to ethanol by fermentation. Ethanol is the starting material for producing acetone, butanol, citric acid and lactic acid. The mechanism of the enzymatic hydrolysis of cellulose are reasonably explained in terms of the sequential action of three different types of enzymes, endo-cellulase, ex-cellulase, and $\beta$ -glucosidase. The goal of this work was to investigate the cellulose hydrolysis pretreated polar with various concentration NaOH, the crystallinity of cellulose, lignin contents and the degree of hydrolysis.

• Journal of the Korean Society of Food Culture
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• v.36 no.2
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• pp.210-217
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• 2021

This study evaluated the biological activity and cytoprotective effect of guava (Psidium guajava L.) branch against oxidative stress. The contents of vitamin C, beta-carotene, total carotenoids, quercetin and catechin determined were 26.783, 43.676, 65.083, 58.245, and 8.309 mg/100 g, respectively. To measure antioxidant activity, the guava branch was extracted using various concentrations of ethanol (60, 80, or 100%) and water. The highest content of polyphenols (0.245 mg gallic acid equivalent/mg residue) and flavonoids (0.128 mg cathechin equivalent/mg residue) was found in the 100% ethanol extract of the branch (E100). Moreover, E100 also possessed the highest radical scavenging activities and showed the highest inhibition rate of α-glucosidase (77.692%). E100 was the most effective extract to impart cytoprotectant activity against oxidative stress in HepG2 cells. Taken together, our results determine the promising antioxidant activity of guava branch, and indicate the potential to be applied as a natural antioxidant.

• Journal of Soil and Groundwater Environment
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• v.28 no.5
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• pp.68-77
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• 2023

The effect of soil damage on the physicochemical characteristics and activity of the soil microbial community is not well known. This study investigates this relationship by analyzing 11 soil samples collected from various points of soil damage across Gyeonggi-do. Soil damage resulted from forest fires, landslides, and development areas, with their impacts most severe on the topsoil layer (0-30 cm). Dehydrogenase and β-glucosidase activities were notably higher at locations damaged by forest fires compared to other sites. While enzyme activities in soils influenced by landslides and development areas were relatively low, sites with a pollution history exhibited elevated dehydrogenase activity, likely due to past microbial response to the pollution. Additionally, an assessment of carbon substrate usability by soil microorganisms indicated higher substrate availability in areas impacted by forest fires, contrasting with lower availability in landslide and development sites. Statistical analysis revealed a positive correlation between organic content of sand and clay and microbial activity. These findings provide valuable insights into soil damage and associated restoration research, as well as management strategies.

• Microbiology and Biotechnology Letters
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• v.9 no.4
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• pp.213-218
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• 1981

The molecular weight of the purified $\beta$-galactosidase of Penicillium sp. was estimated to be 130000 by both Sephadex G-200 gel filtration and SDS-polyacrylamide del electrophoresis. The SDS-electrophoresis gave two protein bands corresponding to the two molecular weights of 130000 and 70000. These results indicated that the enzyme consisted of two probably identical subunits which had a molecular weight of 70000. The optimum pH of the enzyme activity was 4.7 and maximum activity appeared at 5$0^{\circ}C$. The stable pH range for the enzyme was from 4.5 to 7.0. The purified $\beta$-galactosidase had no metal ion requirement for its activity or stability. The enzyme activity was inhibited by C $u^{++}$(1mM)and galactose (100mM). The hydrolysis of lactose in 5% lactose solution, pasteurized milk and 10% skim milk solution were 69.5%, 88.7% and 72.6% after 4 hr incubation at 5$0^{\circ}C$, when 10 units of $\beta$-glucosidase were used per $m\ell$ of the substrate solutions.s.

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.549-554
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• 1990

Glycosidically bound fraction was separated from apricot by Amberlite XAD-2 adsorption and eluted with methanol. Aglycones were liberated from the bound fraction by enzymatic hydrolysis, acid hydrolysis or by means of simultaneous distillation-extraction at pH 3.0. A total of 40 components were identified in three bound volatile fractions. Besides linalool oxide, linalool. ${\alpha}-terpineol$, nerol, geraniol, benzyl alcohol and 2-phenylethyl alcohol, previously reported as glycosidically bound volatiles, the following components were identified for the first time as glycosidically bound volatiles in apricot: 2,6-dimethyl-3,7-octadiene-2,6-diol , 3.7-dimethyl-1,5-octadiene-3,7-diol, (E)- and (Z)-2.6-dimethyl-2,7-octadiene-1,6-diol, $3,4-didehydro-{\beta}-ionol,\;3-oxo-{\alpha}-ionol$, $3-hydroxy-7,8-dihydro-{\beta}-ionol,\;3-oxo-7,8-dihydro-{\alpha}-ionol ,\;3-hydroxy-{\beta}-ionone$, eugenol, 4-hydroxyethylphenyl acetate and 2,3-dihydrobenzofuran.