• Proceedings of the Korean Society of Life Science Conference
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• 2001.09a
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• pp.53-53
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• 2001

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.190-196
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• 1998

A new sampling and size exclusion chromatography (SEC) method for the analysis of underivatized cellulose are established. In this method, cellulose materials are first dissolved in N-methylmorpholine N-oxide (NMMO) and diluted by adding dimethyl sulfoxide (DMSO) to make the sample solutions of about 0.1% in 50/50 NMMO/DMSO (w/w). Sample solutions are analyzed using a glucose-treated divinylbenzene (DVB) SEC column and DMSO containing 0.05M LiBr and 2.5 blank as the eluant. The flow rate was constant at 1 mL/min and the whole SEC system including the column was heated at $80^{\circ}C$ to reduce the viscosity of DMSO. Addition of 0.05 M LiBr eliminated SEC baseline drifting, and addition of 2.5 blank seems to reduce the interaction between the sample and the column packing. SEC molecular weights were determined using a calibration curve constructed from a series of narrow pullulan standards, and they were used to measure the degree of degradation during two different pulp-to-sponge processings.

• Applied Biological Chemistry
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• v.28 no.1
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• pp.1-7
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• 1985

Exo-maltotetraohydrolase produced by Pseudomonas stutzeri IAM 12097 was characterized with respect to substrate specificity, the reaction products and hydolysis rate on various carbohydrates. Maltopentaose, maltoheptaose, soluble starch, amylose, amylopectin, oyster glycogen and gelatinized starch of corn, potato, glutinous rice, green banana and arrow root were hydolyzed by this enzyme, but ${\alpha},{\beta},{\gamma}-cyclodextin$, sucrose, raffinose, lactose, pullulan, maltose, maltotriose and maltotetraose were not hydrolyzed. Among oligosaccharides, maltohexaose was favorably hydrolyzed by this enzyme and the main reaction product of oligosaccharides and polysaccharides was maltotetraose. Addition of pullulanase to this enzyme increased the hydolysis rate on gelatinized starches. tut it did not on raw starches. Among various starches, corn starch was favorably hydrolyzed by this enzyme, whereas it acted on potato starch, arrow root starch and high amylose corn starch weakly.

• Korean Journal of Food Science and Technology
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• v.16 no.4
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• pp.398-402
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• 1984

These experiments were conducted to investigate the substrate specificity, the hydrolysis products on the various carbohydrates and the hydrolysis rate on the various raw starches of the two purified glucoamylase produced by Rhizopus oryzae. Both of the glucoamylases hydrolyzed amylose, amylopectin, glycogen, soluble starch, pullulan, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, maltoheptaose and maltooctaose, but did not act on ${\alpha}-cyclodextrin$, ${\beta}-cyclodextrin$, raffinose, sucrose and lactose. When the reaction mixture of glucoamylase and polysaccharides were incubated $37^{\circ}C$for 32 hours, glucoamylase I hydrolyzed amylopectin, soluble starch and amyloses completely, but hydrolyzing glycogen up to only about 88%. Glucoamylase II hydrolyzed the previous four polysaccharides up to about 100%. Both of the glucoamylases produced only glucose for various substrates and did not have any ${\alpha}-glucosyl$ transferase activity. Both of the glucoamylases hydrolyzed raw glutinous rice starch almost complety, wheras they acted on raw potato starch, raw green banana starch, raw arrow root starch, raw corn starch, raw yam starch and raw high amylose corn starch weakly. Glucoamylase II hydrolyzed raw starches at the higher rate than glucoamylase I.

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.533-538
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• 1990

In polysaccharide fermentation with Aureobasidium pullulans, the aeration effects on the production of polysaccharide and the rheological properties of fermentation broth were studied. The increase of the aeration rates from 0.5 to 2.0vvm at 500 rpm yielded the maximum specific production rate of polysaccharide from 0.046 to $0.093 (hr^{-1})$, and the maximum specific growth rate of cells from 0.168 to $0.192 (hr^{-1})$. The viscosity behavior of fermentation broths at the different aeration rates followed the power-law ${\tau}= K({\gamma})^n$. The viscosity attributed by cells was about 10% of the total viscosity of fermentation broth and most of viscosity was attributed by the polysaccharide produced. The relationship between power-law parameters and the concentration of polysaccharide generally satisfied the etㄴrations with the regression coefficient greater than 0.980, $lnK(t)= ln({\tau})_o-n(t)\;ln({\gamma})_o\;and\;K(t)=A P(t)^B$.

• KSBB Journal
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• v.9 no.2
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• pp.133-139
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• 1994

Oligosaccharide formation and the production of transfructosylase and transglucosylase by Aureobasidium pullulans were studied in sucrose or maltose media, respectively. The initial uptake rates of substrate in sucrose-rich media were faster than that in maltose-rich media, also most parts of oligosaccharides formed and other monosaccharides released were utilized progressively as substrate during the cultivation periods. However, when the initial amount of sucrose was raised to $100g/\ell$, high concentration of monosaccharides were liberated, consequently high-level fructose was accumulated unused during fermentation. The biggest molecule of oligosaccharide synthesized was hexasaccharide in all cultivation media examined, of which the organism could not utilize isomalto-oligosaccharide of DP6 synthesized in a maltose-rich medium. The maximum amount of oligosaccharides produced was $58g/\ell$ when $100g/\ell$ of sucrose and $5g/\ell$ of maltose were used as initial substrate. From the early stage of growth both fructooligosaccharides and isomalto-oligosaccharides were synthesized and progressively utilized as substrates during the fermentation. Based on the experimental results, it was suggested that maltose could induce both transfructosylase and transg1ucosylase, whereas sucrose was unable to slimulate transglucosylase formation.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.776-781
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• 2009

A putative cyclomaltodextrinase (BHCD) gene was found from the genome of Bacillus halodurans C-125, which encodes 578 amino acids with a predicted molecular mass of 67,279 Da. It shares 42-59% of amino acid sequence identity with common cyclomaltodextrinase (CDase)-family enzymes. The corresponding gene was cloned by polymerase chain reaction (PCR) and the dimeric enzyme with C-terminal 6-histidines was successfully overproduced and purified from recombinant Escherichia coli. BHCD showed the highest activity against ${\beta}-CD$ at pH 7.0 and $50^{\circ}C$. Due to its versatile hydrolysis and transglycosylation activities, BHCD has been confirmed as a member of CDases. However, BHCD can be distinguished from other typical CDases on the basis of its novel multisubstrate specificity. While typical CDases have over 10 times higher activity on ${\beta}-CD$ than starch or pullulan, the CD-hydrolyzing activity of BHCD is only 2.3 times higher than pullulan. In particular, it showed significantly higher activity ratio of maltotriose to acarbose than other common CDase-family enzymes.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.792-799
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• 2007

A gene encoding a putative glycogen-debranching enzyme in Sulfolobus shibatae(abbreviated as SSGDE) was cloned and expressed in Escherichia coli. The recombinant enzyme was purified to homogeneity by heat treatment and Ni-NTA affinity chromatography. The recombinant SSGDE was extremely thermostable, with an optimal temperature at $85^{\circ}C$. The enzyme had an optimum pH of 5.5 and was highly stable from pH 4.5 to 6.5. The substrate specificity of SSGDE suggested that it possesses characteristics of both amylo-1,6-glucosidase and $\alpha$-1,4-glucanotransferase. SSGDE clearly hydrolyzed pullulan to maltotriose, and $6-O-\alpha-maltosyl-\beta-cyclodextrin(G2-\beta-CD)$ to maltose and $\beta$-cyclodextrin. At the same time, SSGDE transferred maltooligosyl residues to the maltooligosaccharides employed, and maltosyl residues to $G2-\beta-CD$. The enzyme preferentially hydrolyzed amylopectin, followed in a decreasing order by glycogen, pullulan, and amylose. Therefore, the present results suggest that the glycogen-debranching enzyme from S. shibatae may have industrial application for the efficient debranching and modification of starch to dextrins at a high temperature.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.532-532
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• 2012

탄소 나노튜브(carbon nanotube, CNT)를 사용하여 AC 구동 방식의 organic light emitting devices (OLED)를 만들었다. 이 소자는 ITO가 코팅된 유리 위에 유전체 층, 유기 발광층 그리고 맨 위의 금속 전극 층으로 총 3개의 층으로 구성되어있다. 유전물질로써는 cyanoethyl pullulan (CRS)를 N,N dimethylformamide (DMF) 용매에 녹여 ITO층 위에 코팅하였고, 유기발광 물질로 poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV)를 chloroform (CF)에 녹여 유전체 층 위에 코팅하였다. CNT를 MEH-PPV와 섞어서 유기발광 혼합물을 만들고 난 후, 유전체층 위에 코팅하였다. 마지막으로 알류미늄 전극을 시료 위에 코팅하였다. 소자에서 사용한 MEH-PPV에 의해 나오는 붉은색 발광을 확인 한 결과, CNT를 사용한 OLED 소자가 CNT를 사용하지 않는 소자보다 brightness가 좋았고, 전류도 더 작게 흘렀다. CNT의 농도에 따라 brightness의 변화는 경향을 나타냈다. CNT에 의한 percolation 효과 때문에 이러한 OLED 시료의 성능 향상이 이루어졌음을 입증하는 실험결과를 발표에서 설명할 예정이다.

• Journal of Microbiology and Biotechnology
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• v.2 no.1
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• pp.7-13
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• 1992

A moderately thermophilic, alkalophlic and powerful crystalline cellulose-digesting bacterium, Bacillus K-12, was isolated from filter paper wastes and found to be similar to Bacillus circulans or Bacillus pumilis, except for its ability to grow at a moderately high pH and temperature. The isolate grew at a pH ranging from 6 to 10 and at a temperature ranging from 35 to $65^{\circ}C$ and produced a large amount of cellulase components containing avicelase, xylanase, CMCase, and FPase when grown in avicel medium for 5 to 7 days at $50^{\circ}C$. The crude enzyme preparation from the culture broth hydrolyzed xylan, raw starch, pullulan and ${\beta}-1,3$ glucan such as laminarin. Furthermore, the enzyme hydrolyzed crystalline cellulose to cellobiose and glucose and had a broad pH activity curve (pH 6~9). The enzyme was stable up to $70^{\circ}C$.