• Microbiology and Biotechnology Letters
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• v.50 no.3
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• pp.395-403
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• 2022

In this study, we identified that the fermentation of Korean indigenous probiotics and red ginseng produced ginsenoside compound K (CK) from major ginsenosides. Based on whole genome sequencing of 19 probiotics species, β-glucosidase, α-arabinofuranosidase, β-xylosidase, and α-rhamnosidase related to bioconversion of ginsenosides are identified in the genome of 19 species, 3 species, 6 species, and 8 species, respectively. Among the 19 probiotics species, Bifidobacterium longum CBT BG7 converted from ginsenoside Rb1 to CK, and both B. breve CBT BR3 and B. lactis CBT BL3 converted ginsenoside Rb1 to Rd. The final concentration and yield of ginsenoside F2 and CK were higher in the fermentation with the nondisrupted cells than with disrupted cells. The combination of both CBT BG7 and BL3, and CBT BG7 and BR3 showed higher amounts of F2 than CBT BG7 only. CBT BG7 with adding α-amylase increased the amounts of F2. In this study, we identified that the fermentation of both Korean indigenous probiotic bacteria CBT BG7, BR3 and BL3, and red gingseng is able to produce CK, a bioactive compound that promotes health benefits.

• The Journal of Internal Korean Medicine
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• v.41 no.4
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• pp.599-611
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• 2020

Objectives: The aim of this study was to evaluate the effects of Hwanggi-tang on glucose digestion, uptake, and metabolism in murine C2C12 myotubes. Methods: Hwanggi-tang was prepared according to the Dong-ui-bo-gam (≪東醫寶鑑≫) prescription by 70% ethanol extraction. The effect on glucose digestion was examined by determining the inhibitory effect of Hwanggi-tang on α-glucosidase activity. We also compared and verified the gene and protein expression of genes related to glucose uptake in C2C12 myotubes treated with Hwanggi-tang or insulin. Glucose metabolism was assessed by the expression levels of associated enzymes. Results: Hwanggi-tang caused a dose-dependent inhibition of α-glucosidase activity, induced glucose uptake by activation of the PI3K/Akt/mTOR pathway in the insulin signaling pathway, and promoted glucose oxidation and β-oxidation. Conclusions: Hwanggi-tang exerts an anti-diabetic effect on murine myotubes by inhibiting glucose digestion and inducing glucose uptake and consumption.

• 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 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.

• Journal of Food and Nutrition Research
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• v.10 no.1
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• pp.32-40
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• 2022

Diabetes is a chronic metabolic disease with a high prevalence worldwide. Beet (Beta vulgaris) is a plant that is widely used in many countries and has various biological activities. In this study, we aimed to evaluate the antidiabetic effect of a B. vulgaris mixture (BM). In the in vitro evaluation, we measured the inhibitory activities of α-amylase and α-glucosidase, performed the oral starch tolerance test (OATT) and oral sucrose tolerance test (OSTT) in Sprague Dawley (SD) rats, and evaluated the clinical symptoms, oral glucose tolerance test (OGTT), number of blood cells, and insulin resistance in db/db mice. BM showed an inhibitory effect against α-amylase and α-glucosidase activity and decreased the blood glucose increased in the OATT and OSTT. In the diabetes mouse model, BM alleviated the general symptoms of diabetes and OGTT results showed a decrease in the increased blood sugar level. Regarding diabetes-related tissue weight, BM decreased the reduced pancreatic weight and showed an effect on diabetes-related factors of blood. Histological analysis indicated that BM decreased insulin concentration, insulin resistance, and insulin secretion ability in serum, and increased insulin concentration in the islets of Langerhans. These results demonstrate that BM has an antidiabetic effect through the regulation of glycolytic enzymes and β cell activity in the pancreas.

• Journal of Physiology & Pathology in Korean Medicine
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• v.37 no.1
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• pp.1-8
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• 2023

The aim of this study is to evaluate the antidiabetic effect of the water extract of Aurantii fructus immaturus (WAF), in diabetic models using enzyme, cells and mice, and to suggest a putative mechanism explaining its antidiabetic effect. In an enzyme model using the enzyme α-glucosidase, WAF had no significant effect on α-glucosidase, as compared with acarbose, an antidiabetic drug. Nonetheless, WAF was capable of reducing the blood glucose levels during oral sucrose tolerance test and oral glucose tolerance test, implying that there would be other antidiabetic pathways in no relation to inhibition of α-glucosidase. In cell models using RIN-m5f β-cells and L6 myotubes, WAF, at its non-cytotoxic doses, augmented the secretion of insulin in RIN-m5f β-cells stimulated with 5 mM glucose. In addition, it enhanced the cellular uptake of glucose in L6 myotubes stimulated with deprivation of glucose for 12 h. Therefore, it is most likely that WAF may exert its antidiabetic effects, at least in part, by enhancing insulin secretion and glucose uptake. Meanwhile, in diabetic mice induced with peritoneal injection of streptozotocin (STZ), WAF significantly improved fast blood glucose levels, glycosylated hemoglobin levels, body weight loose, blood pressure, and diabetic adverse effects on functions of the kidney and the liver. Taken together, the water extract of Aurantii fructus immaturus may ameliorate diabetes in mice injected with STZ, at least in part, by enhancing insulin secretion and glucose uptake.

• Journal of Microbiology and Biotechnology
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• v.29 no.3
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• pp.410-418
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• 2019

To investigate a novel ${\beta}$-glucosidase from Bifidobacterium breve ATCC 15700 (BbBgl) to produce compound K (CK) via ginsenoside $F_2$ by highly selective and efficient hydrolysis of the C-3 glycoside from ginsenoside Rd, the BbBgl gene was cloned and expressed in E. coli BL21. The recombinant BbBgl was purified by Ni-NTA magnetic beads to obtain an enzyme with specific activity of 37 U/mg protein using pNP-Glc as substrate. The enzyme activity was optimized at pH 5.0, $35^{\circ}C$, 2 or 6 U/ml, and its activity was enhanced by $Mn^{2+}$ significantly. Under the optimal conditions, the half-life of the BbBgl is 180 h, much longer than the characterized ${\beta}$-glycosidases, and the $K_m$ and $V_{max}$ values are 2.7 mM and $39.8{\mu}mol/mg/min$ for ginsenoside Rd. Moreover, the enzyme exhibits strong tolerance against high substrate concentration (up to 40 g/l ginsenoside Rd) with a molar biotransformation rate of 96% within 12 h. The good enzymatic properties and gram-scale conversion capacity of BbBgl provide an attractive method for large-scale production of rare ginsenoside CK using a single enzyme or a combination of enzymes.

• Journal of Microbiology and Biotechnology
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• v.31 no.8
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• pp.1123-1133
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• 2021

Biodegradation is the key process involved in natural lignocellulose biotransformation and utilization. Microbial consortia represent promising candidates for applications in lignocellulose conversion strategies for biofuel production; however, cooperation among the enzymes and the labor division of microbes in the microbial consortia remains unclear. In this study, metagenomic analysis was performed to reveal the community structure and extremozyme systems of a lignocellulolytic microbial consortium, TMC7. The taxonomic affiliation of TMC7 metagenome included members of the genera Ruminiclostridium (42.85%), Thermoanaerobacterium (18.41%), Geobacillus (10.44%), unclassified_f__Bacillaceae (7.48%), Aeribacillus (2.65%), Symbiobacterium (2.47%), Desulfotomaculum (2.33%), Caldibacillus (1.56%), Clostridium (1.26%), and others (10.55%). The carbohydrate-active enzyme annotation revealed that TMC7 encoded a broad array of enzymes responsible for cellulose and hemicellulose degradation. Ten glycoside hydrolases (GHs) endoglucanase, 4 GHs exoglucanase, and 6 GHs β-glucosidase were identified for cellulose degradation; 6 GHs endo-β-1,4-xylanase, 9 GHs β-xylosidase, and 3 GHs β-mannanase were identified for degradation of the hemicellulose main chain; 6 GHs arabinofuranosidase, 2 GHs α-mannosidase, 11 GHs galactosidase, 3 GHs α-rhamnosidase, and 4 GHs α-fucosidase were identified as xylan debranching enzymes. Furthermore, by introducing a factor named as the contribution coefficient, we found that Ruminiclostridium and Thermoanaerobacterium may be the dominant contributors, whereas Symbiobacterium and Desulfotomaculum may serve as "sugar cheaters" in lignocellulose degradation by TMC7. Our findings provide mechanistic profiles of an array of enzymes that degrade complex lignocellulosic biomass in the microbial consortium TMC7 and provide a promising approach for studying the potential contribution of microbes in microbial consortia.

• Journal of Ginseng Research
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• v.46 no.1
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• pp.1-10
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• 2022

Ginseng has been well-known as a medicinal plant for thousands of years. Bacterial endophytes ubiquitously colonize the inside tissues of ginseng without any disease symptoms. The identification of bacterial endophytes is conducted through either the internal transcribed spacer region combined with ribosomal sequences or metagenomics. Bacterial endophyte communities differ in their diversity and composition profile, depending on the geographical location, cultivation condition, and tissue, age, and species of ginseng. Bacterial endophytes have a significant effect on the growth of ginseng through indole-3-acetic acid (IAA) and siderophore production, phosphate solubilization, and nitrogen fixation. Moreover, bacterial endophytes can protect ginseng by acting as biocontrol agents. Interestingly, bacterial endophytes isolated from Panax species have the potential to produce ginsenosides and bioactive metabolites, which can be used in the production of food and medicine. The ability of bacterial endophytes to transform major ginsenosides into minor ginsenosides using β-glucosidase is gaining increasing attention as a promising biotechnology. Recently, metabolic engineering has accelerated the possibilities for potential applications of bacterial endophytes in producing beneficial secondary metabolites.

• Microbiology and Biotechnology Letters
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• v.52 no.1
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• pp.76-87
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• 2024

Halophilic bacteria are promising reservoirs for halotolerant enzymes that have gained much attention in biotechnological applications due to their remarkable activity and stability. In this study, 62 halophilic bacterial strains isolated from a solar saltern were screened for the production of various extracellular enzymes. The results revealed that 31 strains (50%) were positive for amylase production while 26 strains (41.9%) were positive for protease. Further, 22 strains (35.48%) exhibited β-glucosidase activity and only 17 (27.41%) demonstrated lipase activity. Of the investigated halophiles, ten strains growing in the presence of ≥15% NaCl (w/v) were selected and identified based on their 16S rRNA gene sequences as Halomonas meridiana, Salinivibrio costicola, Virgibacillus oceani, Virgibacillus marismortui, Marinobacter lipolyticus, Halobacillus karajensis, Salicola salis, Pseudoalteromonas shioyasakiensis, Salinicoccus amylolyticus, and Paracoccus salipaludis. Therefore, the present study highlights the diversity of the culturable halophilic bacteria in a Mediterranean solar saltern, harboring various valuable halotolerant enzymes.