• Microbiology and Biotechnology Letters
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• v.45 no.4
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• pp.277-283
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• 2017

To produce sweet liquor without artificial sweeteners, 8 traditional rice pre-treatment methods (juk, beombeok, seolgitteok, gumeongtteok, mulsongpyeon, injeolmi, gaetteok, and godubap) were analyzed in this study. The formation of sugars with the help of ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase using nuruk as a substrate has been previously confirmed. During the early stages of the pre-treatment processes, the amount of maltose produced (in descending order of its concentration) by ${\alpha}$-amylase was observed to be as follows: gaetteok > seolgitteok > beombeok > mulsongpyeon > juk > injeolmi > gumeongtteok > godubap. However, changes in maltose concentrations with respect to the pre-treatment processes after 48 hours were observed to be as follows: injeolmi > beombeok = godubap > gumeongtteok > gaetteok = mulsongpyeon > seolgitteok > juk. Maltose produced using either ${\alpha}$-amylase or ${\beta}$-amylase showed similar results. Glucoamylase produced 10 mg/ml of glucose during the godubap process, which was the highest amount of glucose among all the methods. Moreover, when ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase were used concurrently, glucoamylase increased glucose production in the later stages. Therefore, the possibility of producing sweet liquor without employing artificial sweeteners was confirmed, even if the amount of sugar in the liquor varied with the pre-treatment process.

• Journal of Life Science
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• v.12 no.4
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• pp.477-482
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• 2002

As a biological model system for the production of an active antibacterial peptide, we have attempted the expression and secretion of insect defensin in Saccharomyces cerevisiae. Nucleotide sequences encoding mature defensin composed of 40 amino acids were fused in frame with promoter and signal sequence of Saccharomyces diastaticus glucoamylase, and mating factor $\alpha$ l[MF $\alpha$1] prosequence. The host strain, S. cerevisiae 2805 was transformed with the resulting plasmid, pSMFll The secretion of functional defensin was confirmed by growth inhibition zone assay using Micrococcus luteus as a test organism. Insect defensin was secreted to the culture supernatant in biologically active form by glucoamylase signal sequence and mating factor $\alpha$1 prosequence. Most of antibacterial activity was detected in the culture supernatant. Defensin was also active against Staphylococcus aureus and Listeria monocytogenes.

• Korean Journal of Microbiology
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• v.29 no.2
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• pp.104-110
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• 1991

The glucoamylase of Schwanniomyces castellii was purified to homogeneity from the culture filtrate. the purified enzyme was a glycoprotein with a molecular mass of about 145 KDa, which was monomeric protein with an isoelectric point of 4.3. The pH and temperature optima were 5.5 and 40.deg.C, respectively. The enzyme was fairly stable up to 50.deg.C and at acid pH range (pH 4.5-6.0). The apparent Km of the enzyme toward soluble starch, isomaltose and pullulan were 3.84, 0.51 and 13.7 mg/ml, respectively. The analysis of amino acid composition on this enzyme was found to be acidic protein like other fungal glucoamylase. The amino acid sequence of N-terminal peptide consisted of Ala-Pro-Ala-Asp-Gly-Ile-Gly-Asp-X-Ala-X-Ala.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.519-523
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• 1992

The glucoamylase of Candida tsuubaensis was purified to homogeneity form culture filtrate by means of ultrafiltration, Sephacryl S-200 gel filtration and Sp-Sephadex C-50 chromatography. The purified enzyme was a glycoprotein with a molecular mass of approximately 50 kDa, which was a monomeric protein. Km values were 5.8 mg/ml for soluble starch and 0.04 mM for maltose. Glucoamylase also released only glucose from both pullulan and isomaltose. The analysis of amino acid composition revealed that the enzyme contained a high content of acidic and polar amino acids. In addition, Western blotting analysis indicates that C. tsukubaensis glucoamylase is resistant to glucose repression.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.203-207
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• 1993

Five different secretion vectors were constructed by varying the signal sequences and .alpha.-antitrypsin (.alpha.1-AT) a numan secretory protein, was produced from yeast cells. The signal sequences used are those of acid phosphatase (PH05) and .alpha.-factor (M f.alphal1) of Saccharomyces cerevisiae, glucoamylase (STA1) of Saccharomyces diastaticus, and human .alpha.1-AT. Four vectors directed the efficient secretion of .alpha.1-AT ito the culture media. The secretion vector carrying the glucoamylase signal sequence (pGAT11) showed the highest efficiency of secretion. About 70% of .alpha.1-AT produce dwere secreted into the media. The endo H treatment of partially purified .alpha.1-AT indicates that the secreted .alpha.1-AT appeared to be glycosylated. This glycosylation pattern was altered when amino acid substitution mutations were introduced at the three glycosylation sites of .alpha.-AT.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.2
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• pp.128-135
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• 1987

Extracellular ${\alpha}-amylase$, ${\beta}-amylase$ and glucoamylase produced by a thermophilic and cellulolytic bacterium, Herpetosiphon geysericola CUM 317, were partially purified by salting out with ammonium sulfate and by chromatography on a DEAE-cellulose column and on a CM-cellulose column. The Km values of ${\alpha}-amylase$, ${\beta}-amylase$ and glucoamylase for potato starch were $2.31mg/m{\ell}$, $7.69mg/m{\ell}$, and $8.33mg/m{\ell}$. The molecular weights of ${\alpha}-amylase$, ${\beta}-amylase$ and glucoamylase were calculated to be about 84000 dalton, 76000 dalton and 80000 dalton, respectively.

• Korean Journal of Microbiology
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• v.14 no.2
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• pp.49-49
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• 1976

Enzyme activities, such as glucoamylase dextrinogenic amylase, cellulase, acid protase and neutral protease, of Rhizopus isolated from various substrates collected throughout South Korea are measured, and their enzyme activities are surveyed from taxonomical, ecological and physiological viewpoint. Effect of carbon sources and phytohormones on the amylalse production of Rhizopus are also measured. Among the 735 strains of Phizopus isolated, strain number 587 exhibiting most prominent dextrinogenic amylase and netral protease activity is selected as the best strain, and the strain number 673, 108, 329, 165 and 728 are seleted for their predominant cellulase, acid protease, glucoamylase, dextrinogenic amylase and neutral protease activities, respectively. R.acidus and R.nigricans which exhibited relatively higher callulalse activity, showed lower activities for both amylase. R.tritici exhibited higher protease activity. The relations between activities and various substrates of wild strains are not outstnading difference, although the strains isolated from inland region exhibited more or less higher amylase and cellulase activities, than those of coast region, generally. Lactose and dextrin are most effective carbon sources for glucoamylase and dextrinogenic amylase production of the Rhizopus niveus, respectively. Although all phytohormones tested are effective for production of amylase by the Rhizopus strains, except nicotinamide for glucoamylase production, biotin and ascorbate are most effective for dextrinogenic amylase and glucoamylase production, respectively.

• Korean Journal of Microbiology
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• v.14 no.2
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• pp.47-56
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• 1976

Enzyme activities, such as glucoamylase dextrinogenic amylase, cellulase, acid protase and neutral protease, of Rhizopus isolated from various substrates collected throughout South Korea are measured, and their enzyme activities are surveyed from taxonomical, ecological and physiological viewpoint. Effect of carbon sources and phytohormones on the amylalse production of Rhizopus are also measured. Among the 735 strains of Phizopus isolated, strain number 587 exhibiting most prominent dextrinogenic amylase and netral protease activity is selected as the best strain, and the strain number 673, 108, 329, 165 and 728 are seleted for their predominant cellulase, acid protease, glucoamylase, dextrinogenic amylase and neutral protease activities, respectively. R.acidus and R.nigricans which exhibited relatively higher callulalse activity, showed lower activities for both amylase. R.tritici exhibited higher protease activity. The relations between activities and various substrates of wild strains are not outstnading difference, although the strains isolated from inland region exhibited more or less higher amylase and cellulase activities, than those of coast region, generally. Lactose and dextrin are most effective carbon sources for glucoamylase and dextrinogenic amylase production of the Rhizopus niveus, respectively. Although all phytohormones tested are effective for production of amylase by the Rhizopus strains, except nicotinamide for glucoamylase production, biotin and ascorbate are most effective for dextrinogenic amylase and glucoamylase production, respectively.

• Journal of Microbiology
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• v.37 no.1
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• pp.35-40
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• 1999

Sporulation-specific glucoamylase (SGA) gene was isolated from genomic library of Saccharomyces diastaticus 5114-9A by using glucoamylase non-producing mutant of S. diastaticus as a recipient. When the glucoamylase activities of culture supernatant, periplasmic, and intracellular fraction of cells transformed with hybrid plasmid containing SGA gene were measured, the highest activity was detected in culture supernatant. SGA produced by transformant and extracellular glucoamylase produced by S. diastaticus 5114-9A differed in enzyme characteristics such as optimum temperature, thermostability, and resistance to SDS and urea. But the characteristics of SGA produced by sporulating yeast cells and vegetatively growing transformants were identical.

• Journal of Microbiology and Biotechnology
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• v.3 no.3
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• pp.204-208
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• 1993

A fully automatic image analysis method was applied to obtain detailed data on morphological parameters of a glucoamylase fermentation broth with Aspergillus niger No. PFST-38. a mutant strain for glucoamylase hyperproducer. In the initial stage of fermentation. there was an increase in hyphal length. whereas at the end of the fermentation a decrease in hyphal length and increase in hyphal thickness were observed. The percentage of clumps declined with dilution and the influence of shear stress upon hyphal length was negligible. It was found that the slower the decrease in the main hyphal length and the number of tips with the fermentation time. the higher the glucoamylase production rate was recorded. The production rate of glucoamylase was closely related to the increase in the hyphal thickness.