• Korean Journal of Microbiology
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• v.52 no.2
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• pp.220-225
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• 2016

To improve antioxidant glutathione (GSH) content and saccharification ability in sake yeasts of Saccharomyces cerevisiae, the ${\gamma}$-glutamylcysteine synthetase gene (GSH1) from S. cerevisiae, glucoamylase gene (GAM1) and ${\alpha}$-amylase gene (AMY) from Debaryomyces occidentalis were co-expressed in sake yeasts for manufacturing a refreshing alcoholic beverage abundant in GSH from rice starch. The extracellular GSH content of the recombinant sake yeasts increased 1.5-fold relative to the parental wide-type strain. The saccharification ability by glucoamylase of the new yeast strain expressing both GAM1 and AMY genes was 2-fold higher than that of the yeast strain expressing only GAM1 gene when grown in the culture medium containing 2% (w/v) rice starch. It generated 11% (v/v) ethanol from 20% (w/v) rice starch and consumed up to 90% of the starch content after 7 days of fermentation.

• Microbiology and Biotechnology Letters
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• v.10 no.4
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• pp.259-265
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• 1982

These experiments were conducted to investigate the hydrolysis products on the various oligosaccharides of Bacillus cirulans F-2 $\alpha$-amylase, and the hydrolysis rate on the various raw starches of Bacillus circulans F-2 $\alpha$-amylase, Bacillus amylotiquefaciens $\alpha$-amylase and Rhizopus niveus glucoamylase. The results obtained were as follows : 1. Maltotetraose, maltopentaose, maltohexaose, maltoheptaose and maltooctaose were hydrolyzed, but maltose and maltotriose were not hydrolyzed by Bacillus circulans F-2 $\alpha$-amylase. Among maltotetraose, maltopentaose, maltohexaose, maltoheptaose and maltooctaose, especially maltotetraose was hydrolyzed weakly by Bacillus circulans F-2 $\alpha$-amylase. 2. The Hydrolysis rate of oyster glycogen was slightly lower than soluble starch, amylose and amylopectin. 3. The hydrolysis rate of com starch was higher in shaking incubation than in stationary incubation, but the hydrolysis rate of potato starch was not definite according to kinds of enzyme. 4. On com, rice, arrowroot, high amylose corn, banana, sago, yam and potato starch, Bacillus circulans F-2 $\alpha$-amylase exhibited a remarkably higher hydrolysis rate than Bacillus amyloquefaciems $\alpha$-amylase and Rhizopus niveus glucoamylase.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.258-264
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• 2000

Starches from the eight varieties of rice were analyzed using scanning electron microscope(SEM), differential scanning calorimetry(DSC) and X-ray diffractometry, and tested on the starch-granule susceptibility to 15% $H_2SO_4$ and glucoamylase. The shape of starch granules from normal rice varieties and low-amylose mutants were polygonal while shrunken and floury mutants were globular. According to DSC, starches from Nampung CB243 showed higher onset temperature$(T_o)$, completion temperature$(T_c)$ and Punchilmi, Nampung EM90 showed higher enthalpy$({\triangle}H)$ of gelatinization than others. shr showed the highest hydrolysis rate to 15% $H_2SO_4$ while Nampung CB243 showed the lowest one. Eight varieties of rice starch granules showed A-type pattern on X-ray diffractograms. The lower amylose content rice varieties showed the higher hydrolysis rate treated with glucoamylase.

• Preventive Nutrition and Food Science
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• v.3 no.1
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• pp.98-104
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• 1998

As an efffort ot construct LAB (latice acid bacteria), capable of utilizing starch as fermentation substrate without the aid of externally supplied enzymes, plasmid vectors containing the amyL($\alpha$-amylase/pullulansase gene) from Clostridium thermophydrosulfuricum, and glucoamylase cDNA from Asperigillus shirousamii were constructed and introduced itno E. coli and L. lactis. For expression in procaryotes , 1.9kb glucoamylase cDNA encoding the mature form of enzyme was PCR amplified and translationaly fused to a PCR amplified 260 bp fragment containing the promotor and secretion signals of amyl in the same reading frame. The production of $\alpha$-amylase, Apu, and glucoamlase in E. coli and L. lactis was confirmed by enzyme assay and zymography . Enzymeswere detected in both cellpellets and supernatants, indicating theworking of scretion signals in heterologous hosts. The efficiencies of secretion were varibale depending on the gene and host. The highest $\alpha$- amylase acitivity observed was 1.1 units and most activiity was detected from thecell pellets. The degree of gene expression in both hosts and the effect on the growth of hosts were examined.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.258-264
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• 2004

Hypoglycemic effect of Schizandrae Fructus (SF) extract containing in Okchun-san was determined on 3T3-L1 fibroblasts and adipocytes by investigating insulin-like activity, insulin sensitizing activity and ${\alpha}-glucoamylase$ suppressing activity. SF were extracted by using 70% ethanol followed by XAD-4 column chromatography with a mixture solvent of methanol and water, and the fractional extractions were utilized for assaying hypoglycemic effect. No inhibition of ${\alpha}-glucoamylase$ activity of SF was observed. Insulin-like activity 3T3-L1 adipocytes was not shown by SF. A significant insulin sensitizing activity of SF extractions was observed in 3T3-L1 adipocytes, giving SF extractions with 1 ng/ml insulin to reach glucose uptake level increased by 50 ng/ml of insulin alone. When cells were treated with SF (Fr. 4 or 5) plus 1 ng/ml insulin, glucose uptake was increased more than seven times as compared to 1 ng/ml of insulin alone, suggesting that SF extracts increased GLUT4 content by enhancing insulin signaling. These data suggest that SF extracts (especially Fr. 4 and 5) contains an effective insulin sensitizing compounds for hypoglycemic activity in 3T3-L1 adipocytes.

• Food Science and Preservation
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• v.8 no.4
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• pp.405-411
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• 2001

This study was conducted to investigate the effect of rice powder m tile enzyme (protease, $\alpha$-amylase, $\beta$-amylase and glucoamylase) activities of soybean meju fermented by Monascus prepureus and Monascus pilosus. The activities of the enzyme in the rice meju and the soybean meju fermented by M. pilosus were higher than those by M. perpureus. Protease activity of powdered rice meju was higher than that of granular rice meju, while $\alpha$-amylase, $\beta$-amylase and glucoamylase activities were higher in granular rice meju. Protease activity in soybean meju fermented by adding of the cultured medium of Monascus strains(CMM) as a seed inocula were higher than those of the rice powder meju, while $\alpha$-amyulase, $\beta$-amylase and glucoamylase activiities were lower than those of soybean meju by CMM. The concentration of rice powder to show maximum protease activity in soybean meju was also 10% against steamed soybean. But $\alpha$-amylase activity of soybean medju by the CMM added 2% powdered rice showed lower but the activity increaed with an increase in powdered rice, whereas $\beta$-amylase and glucoamylase activiities decreased with an increase in powdered rice. Protease activity of soybean meju fermented by 10% rice meju fermented by M. pilo년 as a seed inocula was higher than that of the meju fermented by Aspergillus oryzae, whereas $\beta$-amylase and glucoamylase activities of the soybean meju showed less than 50%.

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.226-230
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• 2001

High hydrostatic pressure was applied to Foxtail Millet Takju to investigate the effects of high pressure on inactivation of microorganisms and enzymes. Total bacteria, lactic acid bacteria and yeast in untreated Takju were $6.8{\times}10^7,\;1.3{\times}10^8\;and\;8.4{\times}10^7\;CFU/mL$, respectively. Total bacterial count in Takju reduced to $2.2{\times}10^5\;CFU/mL$, while lactic acid bacteria and yeast were sterilized completely when heated at $65^{\circ}C$ for 30 min. Lactic acid bacteria and yeast decreased with the increase of treatment pressure, and pressurization of 400 MPa for 10 min at room temperature sterilized completely the lactic acid bacteria and yeast in Takju. Total bacteria were not sterilized with pressurization of even 600 MPa at room temperature. Total bacteria were completely sterilized at $66^{\circ}C/400\;MPa/60\;min\;and\;66^{\circ}C/600\;MPa/10\;min$. Pressurization of Takju caused a partial inactivation of ${\alpha}-amylase$, and after pressurization at 600 MPa for 10 min at room temperature, 73.2% of the original activity remained. The activity of glucoamylase increased with the increase of treatment pressure. Treatment at $66^{\circ}C/400\;MPa/10\;min$ reduced the activity of ${\alpha}-amylase$ by 59.7% and glucoamylase by 20.5%. ${\alpha}-Amylase$ was inactivated to less than 1.2% of the original activity at $66^{\circ}C/600\;MPa/30\;min$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1221-1226
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• 2003

High hydrostatic Pressure was applied to Foxtail Millet Yakju to investigate the effects of high pressure on inactivation of microorganisms and enzymes. Total bacteria, lactic acid bacteria and yeast in untreated Yakju were $1.5{\times}$10$^4$,1.9${\times}$10$^4$ and 1.4${\times}$10$^4$ CFU/mL, respectively. Total bacterial count was reduced to 4.1${\times}$l0$^2$ CFU/mL, while lactic acid bacteria and yeast were sterilized completely in Yakju heated at $65^{\circ}C$ for 15 min. Lactic acid bacteria and yeast decreased greatly with the increase of treatment pressure, and were sterilized completely in Yakju treated at more than 300 ㎫ for 10 min/$25^{\circ}C$. Total bacteria were not completely sterilized with pressurization of even 600 ㎫ at room temperature and reduced to 2 log cycle even at $65^{\circ}C$. Total bacteria decreased by 2∼3 log cycle with the increase of treatment time from 10 to 60 min at $25^{\circ}C$/300 ㎫. Pressurization of Yakju caused a partial inactivation of $\alpha$ -amylase and glucosamylase, and the activities of $\alpha$ -amylase and glucoamylase decreased by 18.1% and 21.1%, respectively at $25^{\circ}C$/600 ㎫/10 min. Activities of $\alpha$ -amylase and glucoamylase decreased with the increase of temperature, and 22.2% and 32.1% of the original activity were remained with the treatment at $65^{\circ}C$/300 ㎫/10 min, respectively. Enzyme activities decreased slightly with the increase of treatment time at $65^{\circ}C$/300 ㎫.

• Mycobiology
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• v.29 no.4
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• pp.183-189
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• 2001

Extracellular amylase properties were examined with the mycelium of Tricholoma matsutake isolated from ectomycorrhizal roots of Pinus densiflora. The molecular weights of $\alpha$-amylase and glucoamylase were estimated as 34.2 kD and 11.5 kD, respectively, after eluted through Superdex 75 column. The optimum pH of the purified enzyme was found in a range of pH $5.0{\sim}6.0$, with a peak at pH 5.0. The activities of these enzymes were stable from $4^{\circ}C\;to\;30^{\circ}C$. The $\alpha$-amylase of T. matsutake readily hydrolyzed soluble starch and amylose-B, while it weakly hydrolyzed glycogen, dextrin, amylose and amylose-A. The main products of hydrolysis were confirmed to be glucose, maltose and maltotriose on the basis of the similarities in the thin layer chromatographic mobility.

• Korean Journal of Microbiology
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• v.15 no.1
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• pp.31-41
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• 1977

Dextrinogenic and glucoamylase activities of Aspergillus isolated from various habitat-substrates collected through South Korea are measured, and their amylase activities are surveyed in taxonomical and ecological viewpoints. 1. A. flavous group and A.wentii group exhibited higher activities for both amylases than others. 2. In the relations between amylase activity of Asperguillus and their habitat-sub-strates, the strains isolated from meju and cereals exhibited predominant dextrinogenic amylase activity. 3. Dextrinogenic amylase activity of Aspergillus is higher in the strains isolated from southern coast than the other regions. 4. Among the 601 strains of Aspergillus surveryed, strain No.74 and strain No.421 exhibited the most predominant activity for dextrinogenic amylase and glucoamylase, respectively.