• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.823-826
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• 1998

It has been reported that alginic acid hydrolysate retains antimicrobial activity but the enzyme which hydrolyze alginic acid is not developed for industrial use. The authors developed chemical method for hydrolyzing alginic acid. For preparing alginic acid hydrolysate, equal quantity of alginic acid and ascorbic acid were added to water. Then the solution was heated at $121^{\circ}C$ for $20{\sim}30{\;}minutes$. The 4% solution of alginic acid hydrolysate was revealed relative viscosity 1.05, pH 3.2 and opaque whitish-yellow color. By addition of this hydrolysate to nutrient broth with the concentration of 0.1%, the growth of Bacillus sp. isolated from fish meat paste products was inhibited. The fish meat paste products containing 0.3% alginic acid hydrolysate prepared were prolonged their shelf life by 1 day stored at $30^{\circ}C$, 2 days at $20^{\circ}C$ and 4 days at $15^{\circ}C$.

• Journal of Life Science
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• v.29 no.2
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• pp.158-163
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• 2019

The purpose of this study was to isolate a new marine agarase-producing bacterium. Agarase can hydrolyze agar and agarose to produce agarooligosaccharides or neoagarooligosaccharides, which possess many physiological functions. Strain DH-3 was isolated from seawater collected from the coast of Yeosu at Jeollanam province, Korea. A 16S rDNA sequence analysis showed this strain to be Persicobacter sp. DH-3. Extracellular agarase was prepared from culture media of Persicobacter sp. DH-3 and used for characterization. Relative activities at 20, 30, 40, 50, 60, and $70^{\circ}C$ were 50, 55, 70, 100, 90, and 50%, respectively. Relative activities at pH 5, 6, 7, and 8 were 75, 100, 90, and 75%, respectively. The enzyme showed maximum activity at $50^{\circ}C$ in a 20 mM Tris-HCl buffer at pH 6. This enzyme could be useful, as agar is in liquid state at $50^{\circ}C$. Agarase activities were maintained at 80% or more for 2 hr at 20, 30, and $40^{\circ}C$. Thin layer chromatography analysis suggested that Persicobacter sp. DH-3 produced extracellular ${\beta}$-agarases as it hydrolyzed agarose to produce neoagarohexaose and neoagarotetraose. In addition, zymogram analysis confirmed that Persicobacter sp. DH-3 produces at least three agar-degrading enzymes with molecular weights of 45, 70, and 140 kDa. Therefore, it is expected that agarases from Persicobacter sp. DH-3 could be used to produce functional neoagarooligosaccharides.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.503-507
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• 2021

Sodium borohydride, NaBH₄, has many advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFC). When PEMFC is used outdoors as a transport type, it is economical to hydrolyze NaBH₄ using fresh water instead of distilled water. Therefore, in this study, hydrogen was generated using fresh water instead of distilled water during the NaBH₄ hydrolysis process. The properties of NaBH₄ hydrolysis were studied using an activated carbon-supported Co-P-B/C catalyst. Fresh water did not generate tetrahydrate during the NaBH₄ hydrolysis process, and distilled water produced tetrahydrate by-products, which consumed a lot of water during the hydrolysis process, indicating that at the end of the reaction at a high concentration of 25% or more of NaBH₄, dry by-products and unreacted NaBH₄ remained. As a result, when fresh water was used, the hydrogen yield and hydrogen generation rate were higher than that of distilled water at a high concentration of 25% or more of NaBH₄, indicating that it is suitable for use in transport-type fuel cells such as unmanned aerial vehicles.

• Journal of Microbiology and Biotechnology
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• v.31 no.8
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• pp.1163-1174
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• 2021

Casein-derived antioxidant peptides by using microbial proteases have gained increasing attention. Combination of two microbial proteases, Protin SD-NY10 and Protease A "Amano" 2SD, was employed to hydrolyze casein to obtain potential antioxidant peptides that were identified by LC-MS/MS, chemically synthesized and characterized in a oxidatively damaged HepG2 cell model. Four peptides, YQLD, FSDIPNPIGSEN, FSDIPNPIGSE, YFYP were found to possess high 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability. Evaluation with HepG2 cells showed that the 4 peptides at low concentrations (< 1.0 mg/ml) protected the cells against oxidative damage. The 4 peptides exhibited different levels of antioxidant activity by stimulating mRNA and protein expression of the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), as well as nuclear factor erythroid-2-related factor 2 (Nrf2), but decreasing the mRNA expression of Kelch-like ECH-associated protein 1 (Keap1). Furthermore, these peptides decreased production of reactive oxygen species (ROS) and malondialdehyde (MDA), but increased glutathione (GSH) production in HepG2 cells. Therefore, the 4 casein-derived peptides obtained by using microbial proteases exhibited different antioxidant activity by activating the Keap1-Nrf2 signaling pathway, and they could serve as potential antioxidant agents in functional foods or pharmaceutic preparation.

• Journal of Appropriate Technology
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• v.5 no.2
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• pp.91-96
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• 2019

Microalgae do not require much land and make a higher efficient oil production. However, it costs still much higher than other biodiesel resources, such as crops. Sugars charge 80% of culture media when microalgae are massively cultured in the fermenter. This study aims to develop a cost-efficient process for sugar production from Chinese cabbage byproducts. Pre-treatment with 0.25% H₂SO₄ was most effective when chopped cabbage was incubated 50℃/130 rpm for 24 hours. To hydrolyze cabbage cellulose, we used cellulases secreted from Trichoderma. harzianum. T. harzianum was cultured at 28℃/pH 7/130 rpm for five days. Optimal enzymatic activity of cellulase was obtained by incubating at 0.24 FPU/ml/45℃/pH 5/130 rpm for three days. In comparison to other agricultural waste, such as rice straw, green tea leaves, and palm residue, Chinese cabbage produced the highest sugar yield. We found the optimal conditions to produce sugar from Chinese cabbage byproducts as a carbon source to culture biodiesel-producing microalgae. The efficient process developed in this study helps microalgae as a sustainable alternative energy source by cost-down.

• Journal of the Korean Society of Food Culture
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• v.24 no.1
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• pp.84-89
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• 2009

This paper was conducted to evaluate aglycones and carbohydrates produced by acid hydrolysis of three potato glycoalkaloids [(PGA); ${\alpha}$-chaconine, ${\alpha}$-solanine, and demissine] in potatoes. Standard solanidine and demissidine were dissolved in 1N HCl and then heated at $100^{\circ}C$ for 10-120 min. Solanidine was rapidly decomposed during acid hydrolysis and one peak that was identified as solantherene ($M^+$=379) by GC-MS was detected. The transformation solanidine to solanthrene was approximately 50% complete after 10 min, approximately 90% complete after 60 min and 100% complete after 120 min. Demissidine was hydrolyzed using the same method that was used to hydrolyze the solanidine. However, demissidine produced only one peak upon GC-MS ($M^+$=399) analysis and was found to be very stable at increased temperatures. Acidy hydrolysis of ${\alpha}$-chaconine, ${\alpha}$-solanine and demissine resulted in the decomposition of ${\alpha}$-chaconine and ${\alpha}$-solanine to solanidine and solanthrene, respectively. Therefore, this hydrolysis method should not be utilized to produce PGA combining with solanidine as aglycone. The individual carbohydrates produced by the two PGAs by hydrolysis were very stable at increased temperatures; therefore, it was possible to quantify these PGAs based on calculation of the individual carbohydrate content. Conversely, because demissidine produced by the hydrolysis of demissine was extremely stable at increased temperatures, it was possible to quantify the PGA based on the aglycone produced by hydrolysis.

• Korean Journal of Radiology
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• v.21 no.6
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• pp.647-659
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• 2020

Objective: The occurrence of intramyocardial hemorrhage (IMH) and microvascular obstruction (MVO) in myocardial infarction (MI), known as severe ischemia/reperfusion injury (IRI), has been associated with adverse remodeling. APT102, a soluble human recombinant ecto-nucleoside triphosphate diphosphohydrolase-1, can hydrolyze extracellular nucleotides to attenuate their prothrombotic and proinflammatory effects. The purpose of this study was to temporally evaluate the therapeutic effect of APT102 on IRI in rats and to elucidate the evolution of IRI in the acute stage using cardiovascular magnetic resonance imaging (CMRI). Materials and Methods: Fifty-four rats with MI, induced by ligation of the origin of the left anterior descending coronary artery for 60 minutes, were randomly divided into the APT102 (n = 27) or control (n = 27) group. Intravenous infusion of APT102 (0.3 mg/kg) or placebo was administered 15 minutes before reperfusion, and then 24 hours, 48 hours, 72 hours, and on day 4 after reperfusion. CMRI was performed at 24 hours, 48 hours, 72 hours, and on day 5 post-reperfusion using a 7T system and the hearts were collected for histopathological examination. Cardiac function was quantified using cine imaging and IMH/edema using T2 mapping, and infarct/MVO using late gadolinium enhancement. Results: The extent of infarction (p < 0.001), edema (p < 0.001), IMH (p = 0.013), and MVO (p = 0.049) was less severe in the APT102 group than in the control group. IMH size at 48 hours was significantly greater than that at 24 hours, 72 hours, and 5 days after reperfusion (all p < 0.001). The left ventricular ejection fraction (LVEF) was significantly greater in the APT102 group than in the control group (p = 0.006). There was a negative correlation between LVEF and IMH (r = -0.294, p = 0.010) and a positive correlation between IMH and MVO (r = 0.392, p < 0.001). Conclusion: APT102 can significantly alleviate damage to the ischemic myocardium and microvasculature. IMH size peaked at 48 hours post reperfusion and IMH is a downstream consequence of MVO. IMH may be a potential therapeutic target to prevent adverse remodeling in MI.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.3
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• pp.31-37
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• 2010

Chitinases (EC 3.2.1.14) hydrolyze the ${\beta}$-1,4-linkages in chitin, the second most abundant polymer of N-acetyl-${\beta}$-D-glucosamine which is a structural component of protective biological matrices such as fungal cell walls and insect exoskeletons. The glycosyl hydrolases 18 family including chitinases is an ancient gene family widely expressed in archea, prokaryotes and eukaryotes. Since earthworms live in the soil with a lot of microbial activities and fungi are supposed to be a major component of the diet of earthworm, it has been reported that there would be appropriate immune system to protect themselves from microorganisms attacks. In this study, the novel chitinase, EaChi, from the midgut of earthworm, Eisenia andrei, were identified and characterized. To obtain full-length cDNA sequence of chitinase, RT-PCR and RACE-PCR analyses were carried out by using the previously identified EST sequence amongst cDNA library established from the midgut of E. andrei. EaChi, a partial chitinase gene, was composed of 927 nucleotides encoding 309 amino acids. By the multiple sequence alignments of amino acids with other different species, it was revealed that EaCHI is a member of glycosyl hydrolases 18 family, which has two highly conserved domains, substrate binding and catalytic domain.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.186-192
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• 1997

Increased activities of phase 2 enzymes including quinone reductase(QR) have been reported to be associated with protection of animals from neoplastic, mutagenic, and other toxic effects of many carcinogens. In previous study, we found that methanol extract of roasted and defatted perilla meal induced the activity of quinone reductase, an anticarcinogenic marker enzyme, in murine hepalc1c7 cells. Current study showed that unroasted perilla had a limited QR-inducing activity, suggesting that roasting cause the generation of active component(s). Thus we hypothesized that QR inducer in perilla might be covalently linked to sugar moiety and released during roasting process. Methanol extract of defatted raw perilla was subject to acid treatment in order to hydrolyze the potential sugar moiety. Prolonged hydrolysis of methanol extract of defatted raw perilla at $98{\sim}100^{\circ}C$ increased the ability to induce cytosolic QR activity of hepalclc7 cells. Furthermore roasting at 180 and $200^{\circ}C$ resulted in significant induction of QR activity. The result strongly support the idea that QR inducer(s) is present in bound form in raw perilla and released during roasting. Cellular QR activity was induced proportionately with the increase of concentration of methanol extract of roasted perilla. The induction of QR by defatted perilla was also examined in the cytosols of liver, small intestine, stomach, lung and kidney of male ICR mice. Induction patterns showed specificity with respect to target tissue and roasting of perilla. Unroasted perilla meal (defatted) significantly induced QR in liver and lung, while roasted perilla meal induced QR in liver and stomach. The observation that raw perilla showed similar QR induction patterns to roasted perilla is consistent with our proposal that QR inducer(s) is present in bound form and released by physical and chemical treatments as digestive or microbial enzymes could release the inducers from inactive glycoside forms in gastrointestinal tract of mice. In conclusion, perilla could exert protective effect against chemically induced carcinogenesis by inducing phase 2 enzymes in biological systems regardless of chemical and physical process such as roasting.

• Microbiology and Biotechnology Letters
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• v.43 no.2
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• pp.105-111
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• 2015

An alginate degrading enzyme from the Vibrio crassostreae PKA 1002 strain was used to hydrolyze the water extract of Sargassum thunbergii. To obtain the optimum degrading conditions for the S. thunbergii water extract, the mixture of the water extract and enzyme was incubated at 30℃ for 0, 3, 6, 12, and 24 h, and its alginate degrading ability was measured by reducing sugar and viscosity. A temperature of 30℃ for a period of 6 h was found to be the optimal condition for the enhancement of the alginate’s degrading ability. The pH of the enzymatic hydrolysate was not significantly different from that of the water extract. Overall lightness decreased, but redness and yellowness increased after enzymatic hydrolysis. Total phenolic compounds did not differ between the water extract and the enzymatic hydrolysate. DPPH radical scavenging activity and the reducing power of the enzymatic hydrolysate were lower than those of the water extract. However, the chelating effect of the enzymatic hydrolysate (80.08% at 5 mg/ml) was higher than that of the water extract (62.29%). These results indicate that the enzymatic hydrolysate possesses an anti-oxidant activity by way of the action of the chelating effect.