• The Korean Journal of Mycology
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• v.25 no.4 s.83
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• pp.320-329
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• 1997

Botrytis cinerea isolates obtained from infected plants of cucumber, tomato, and strawberry were divided into three groups (sporing, sclerotial, and mycelial types). Of which sclerotial types were the major group. There were no correlations between morphological phenotypes and responses to benzimidazole and dicarboximide fungicides. External structure of conidia of three phenotypes by scanning electron microscope was the same with verrucose surface. Mycelial type was the most virulent on fruits of eggplants. Comparative tests were carried out to examine correlations between the virulence and production of fungal enzymes such as phenol oxidases, pectin methyl esterases (PME), amylases, cellulases, ureases, ${\beta}-glucosidases$, and proteinases. There was no correlation among the phenotypes in production of phenol oxidases and ${\beta}-glucosidases$. However, there were significantly different from each other in PME, amylase, cellulase, urease, and protease activity.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.967-974
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• 2006

Cyclomaltodextrinases (CDases), maitogenic amylases, and neopullulanases share highly conserved primary structures and similar characteristics, and are thus classified into the same family. BLAST search has showed that a variety of bacterial strains harbor putative CDase family genes with several well-conserved motif amino acid sequences. In this study, four degenerate polymerase chain reaction (PCR) primer sets were designed for the detection of CDase genes, on the basis of their highly conserved amino acid blocks (WYQIFP, DGWRLD, LGSHDT, and KCMVW). The PCR detection conditions were optimized and the detection specificity of each for the primer sets was tested against the genomic DNAs isolated from 23 different Bacillus-associated species. Consequently, all tested primer sets evidenced successful amplification of specific PCR products in length, which share 55-98% amino acid sequence identity with known and putative CDases. The primers developed herein, therefore, can be applied for the easy and efficient detection and isolation of CDase family genes for the modification of functional food carbohydrates.

• Journal of Microbiology and Biotechnology
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• v.2 no.3
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• pp.189-196
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• 1992

A $\alpha$-l, 4-D-glucan maltohydrolase $(\beta$-amylase), secreted by the mesophilic aerobic bacterium Bacillus polymyxa No.26, was purified and characterized. The enzyme production was increased after a logarithmic phase of bacterial growth and paralleled with the onset of bacterial sporulation. By applying anion exchange chromatography and gel filtration the enzyme was purified 16.7-fold and had a specific activity of 285.7 units/mg. Two enzyme activities were eluted on a column of DEAE-Sephadex chromatography, and they were designated as E-I for a major enzyme peak and E-II for a minor peak. Of them, E-I enzyme peak was further purified by using gel chromatography. The molecular mass of this enzyme was determined to be 64, 000 daltons and consisted of a single subunit, showing an isoelectric point of 8.9. The enzyme was able to attack specifically the $\alpha$-l, 4-glycosidic linkages in soluble starch and caused its complete hydrolysis to maltose and $\beta$-limited dextrin. This amylolytic enzyme displayed a temperature optimum at $45^\circ{C}$ and a pH optimum at 7.0. The amino acid composition of the purified enzyme was quite similar to the other bacterial $\beta$-amylases reported. Surprisingly, the purified enzyme from this aerobe only exhibited hydrolytic activity on soluble starch, not on starch granules. The degradation of from starch by $\beta$-amylase was greatly stimulated by pullulanase addition. These results differentiated from other $\beta$-amylases reported. Based on a previous result that showed the enzyme system involves in effective degradation of raw starch granules, this result strongly suggested that the purified enzyme (E-I) can be a synergistic part of starch granule-digestion and E-II plays a crucial role in digestion of starch granules.

• The Korean Journal of Food And Nutrition
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• v.11 no.2
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• pp.150-158
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• 1998

Limit dextrin of Korean beer(3 brands) and Japanese beer(21 brands) were separated by ethanol fractionation. Limit dextrin of Korean and Japanese beer was estimated to be 1.1%. 1H-NMR analysis revealed that the limit dextrin showed both signal of $\alpha$-1, 4- and $\alpha$-1, 6- glucosidic linkage with its estimation ratio of average 5.5:1. Limit dextrin was hydrolyzed to glucose with the yield of 57.22% by Aspergillus awamori $\alpha$-glucosidase(24.7 unit) plus human salivay $\alpha$-amylase(2.4 unit) in 100${mu}ell$ of 0.043M acetate buffer at 37$^{\circ}C$ for 5 hour. Among them, limit dextrin of Korean beer showed the highest hydrolysis rate of 76%. Small size sugars (64.8%) removed by ethanol fractionation and limit dextrin(21.4%) hydrolyzed by amylases that is digestable sugar. Non hydrolyzed limit dextrin(13.8%) by the amylases which can be a growth factor of Bifidobacterium in human intestine.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.92-96
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• 1997

A Korean commercial sweet rice drink "Sikhye" showed sucrose, fructose, glucose, maltose, limit dextrin and various size of maltooligosaccharides in HPLC and TLC analysis. Commercial Sikhye was found to contain 0.09% of limit dextrin and 0.2% of rice residue. Limit dextrin in commercial Sikhye showed both signal of $\alpha$-1,4- and $\alpha$-1,6-glucosidic linkage with its estimation ratio of 15:1 by 1H-NMR analysis. This limit dextrin was hydrolyzed to produce various size of maltooligosaccarides with more longer chain than that of traditional Sikhye by pullulanase. Limit dextrin was digested wit enzymes(30units/ml) of $\alpha$-amylase, $\alpha$-glucosidase and glucoamylase from Aspergillus awamori, sweet potato $\beta$-amylase and human salivary $\alpha$-amylase at 37$^{\circ}C$ for 1 hour, respectively. Hydrolysis rates of these amylases on it were higher than in case of traditional sikhye. $\alpha$-Glucosidase plus human salivary $\alpha$-amylase hydrolyzed it to 61.3%. Hydrolysis rates of these amylases on rice residue were lower than that of traditional Sikye. These results suggest that limit dextrin in commercial Sikhye is less effective than isomaltooligosaccharides in traditional Sikhye as a growth factor for Bifidobacterium while rice residue in commercial Sikhye is more effective than that in traditional Sikhye as dietary fiber.ary fiber.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1421-1426
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• 1999

Sixteen domestic barley varieties and subsequently produced malts were evaluated for quality characteristics. Diastatic power(DP), complementary actions of amylases in malt, had a wide $variation(139{\sim}220^{\circ}L)$ among the barley varieties. Some 6-row barley varieties demonstrated significantly high DP values. ${\beta}-\;and\;{\alpha}-amylase$ activities in malts were also significantly influenced by barley varieties. Diastatic power was highly correlated with ${\beta}-amylase$ activity, indicating that the ${\beta}-amylase$ activity was a predominant factor determining saccharifying action in malt. Amylograph was used to indirectly estimate starch-degrading enzymatic activity, and the reduction in amylograph viscosity was associated with ${\alpha}-amylase$ activity. Barley quality factors in relation to enzymatic activity of malt were analyzed, and the barley variety with lower kernel weight and less plumper kernels tended to produce higher starch-degrading enzyme activity. Potential diastatic power, an estimate of bound ${\beta}-amylase$ in raw barley, was associated with diastatic power in the final malt. Potential diastatic power turned out to be an important factor for predicting good malting barley.

• Journal of Microbiology and Biotechnology
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• v.29 no.5
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• pp.765-775
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• 2019

A new ${\alpha}$-amylase-encoding gene (amySL3) of glycoside hydrolase (GH) family 13 was identified in soda lake isolate Alkalibacterium sp. SL3. The deduced AmySL3 shares high identities (82-98%) with putative ${\alpha}$-amylases from the genus Alkalibacterium, but has low identities (<53%) with functionally characterized counterparts. amySL3 was successfully expressed in Escherichia coli, and the recombinant enzyme (rAmySL3) was purified to electrophoretic homogeneity. The optimal temperature and pH of the activity of the purified rAmySL3 were determined to be $45^{\circ}C$ and pH 7.5, respectively. rAmySL3 was found to be extremely halophilic, showing maximal enzyme activity at a nearly saturated concentration of NaCl. Its thermostability was greatly enhanced in the presence of 4 M NaCl, and it was highly stable in 5 M NaCl. Moreover, the enzyme did not require calcium ions for activity, and was strongly resistant to a range of surfactants and hydrophobic organic solvents. The major hydrolysis products of rAmySL3 from soluble starch were maltobiose and maltotriose. The high ratio of acidic amino acids and highly negative electrostatic potential surface might account for the halophilic nature of AmySL3. The extremely halophilic, calcium-independent, and surfactant-resistant properties make AmySL3 a promising candidate enzyme for both basic research and industrial applications.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.649-659
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• 2017

Extremophilic microorganisms have established a diversity of molecular strategies in order to survive in extreme conditions. Biocatalysts isolated by these organisms are termed extremozymes, and possess extraordinary properties of salt allowance, thermostability, and cold adaptivity. Extremozymes are very resistant to extreme conditions owing to their great solidity, and they pose new opportunities for biocatalysis and biotransformations, as well as for the development of the economy and new line of research, through their application. Thermophilic proteins, piezophilic proteins, acidophilic proteins, and halophilic proteins have been studied during the last few years. Amylases, proteases, lipases, pullulanases, cellulases, chitinases, xylanases, pectinases, isomerases, esterases, and dehydrogenases have great potential application for biotechnology, such as in agricultural, chemical, biomedical, and biotechnological processes. The study of extremozymes and their main applications have emerged during recent years.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.529-532
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• 1989

A strain of Streptomyces sp. (YS-221-B) extracellularly produced an inhibitory substance for $\alpha$-D-Glucosidase. The substance was purified 96-fold from culture filtrate by dialysis, heat treatment, adsorption on active carbon, Bio-Gel P-10 and Sephadex G-75 column chromatography with yield of 9.2%. The substance was stable in pH range from 7.0 to 11.0 at 37$^{\circ}C$, and a treatment at 10$0^{\circ}C$ for 20 min diminished only 15% of the original activity. The inhibitor was not inactivated by the treatment of $\alpha$-, $\beta$-amylases, glucoamylases, trypsin and chymotrypsin but inactivated by pyoteases from Streptomyces griseus and Tritirachium album.

• Applied Biological Chemistry
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• v.13 no.3
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• pp.181-186
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• 1970

1) Conditions for the hydrolysis of starch by bacterial liquefying amylase (BLA), saccharifying amylase (BSA) and isoamylase were investigated. Out of four syrups prepared by different combinations of these enzymes, those made by BLA followed by BSA and/or isoamylase were comparable to sucrose syrup in canning of orange segments. 2) Two branched maltooligosaccharides were isolated from the hydrolyzate of starch by BLA and BSA, and their structures were tentatively identified as pentaose and hexaose having an ${\alpha}-1$, 6-linkage at the branching point.