• Journal of Microbiology and Biotechnology
• /
• 제8권6호
• /
• pp.568-574
• /
• 1998

Two types of chitosanases produced from Aspergillus fumigatus KH-94 were purified by ion exchange and gel permeation chromatography. Molecular weights of the enzymes are 22.5 kDa (chitosanase I) and 108 kDa (chitosanase II). pI, optimum pH, and temperature of chitosanase I are 7.3, 5.5, and 70-$80^{\circ}C$, respectively, and those of chitosanase II are 4.8, 4.5~5.5, and 50~$60^{\circ}C$, respectively. Activities of both chitosanases were increased by $Mn^{2+}$ but inhibited by $Cu^{2+}$ and $Hg^{2+}$ . Chitosanase I has endo-splitting activity that hydrolyzes chitopentaose, chitohexaose, and chitosan to chitobiose, chitotriose, and chitotetraose, whereas chitosanase II has exo-splitting activity that hydrolyzes chitobiose and chitosan to glucosamine. Chitosanase II was found to have transglycosylation activity also in the reaction of 2% more chitooligosaccharides as a substrate and at the initial reaction. The higher degree of deacetylation, the stronger activities of chitosanase Iand II toward chitosans. Both chitosanases could hydrolyze chitosan and glycol chitosan but not chitin, cellulose, and carboxymethyl cellulose. To produce higher degree of polymerization of chitooligosaccharides, chitosanase I was used and yielded 80% of recovery.

• 한국염색가공학회지
• /
• 제6권1호
• /
• pp.86-91
• /
• 1994

• 청정기술
• /
• 제20권2호
• /
• pp.108-115
• /
• 2014

셀룰로우스(cellulose)를 5-히드록시메틸푸르푸랄(5-hydroxymethylfurfural, 5-HMF)로 직접 전환하기 위해 이온성 액체 용매하에서 다양한 금속염화물과 산 촉매를 비교 연구하였다. 사용한 금속염화물은 Sn(II), Zn(II), Al(III), Fe(III), Cu(II), Cr(III)를 포함한 염화물을 비교하였으며 산 촉매는 산성 이온성 액체를 고정화하여 사용하였다. 비교를 위하여 $H_2SO_4$, HCl, Amberlyst-15와 DOWEX50x8을 사용하였다. 제조한 촉매의 산도와 산 밀도 특성은 Hammett Indicator 지시약을 통하여 분석하였다. 5-HMF의 선택도 및 수율은 반응온도, 반응시간과 촉매 비를 통하여 확인하였다. 사용한 촉매들 중에서 5-HMF의 선택도는 $CrCl_3-6H_2O$와 $SiO_2-[ASBI]HSO_4$를 사용하였을 때에 가장 높게 나타났으며, 상용화 고체 산인 Amberlyst-15와 DOWEX50x8에 비하여 활성이 높다는 것을 확인할 수 있었다. 5-HMF의 선택도는 산 촉매의 산도와 반응에 사용된 촉매비에 영향이 있음을 확인할 수 있었으며, 반응 중 재수화 반응이 일어나 레불린산(levulinic acid)이 생성된다는 것을 확인하였다.

• 한국수산과학회지
• /
• 제41권4호
• /
• pp.237-242
• /
• 2008

The tunic of Styela clava(SCT) consists of a proteoglycan network. Regenerated cellulose films were prepared by solution casting and coagulation of SCT in N-methylmorpholine-N-oxide(NMMO)/$H_2O$(87/13 wt%). The crystalline structure of powdered SCT was primarily that of cellulose I. The crystalline structure of SCT films exhibited a cellulose II structure, similar to that of viscose rayon. Physical characterization of SCT films and fibers revealed an intrinsic viscosity($\eta$) of 6.35 dL/g, average molecular weight($M_w$) of 423,000 g/M, and fiber density of 1.50 $g/cm^3$ with a moisture regain and water absorption of 10.20% and 365%, respectively. The results were similar to those of cellulose films regenerated from wood pulp. Films prepared with 6 wt% SCT exhibited strong tensile strength, high water absorption, and a greater degree of elongation. Scanning electron micrographs(SEM) of film cross-sections showed a layered, sponge-like structure.

• Journal of the Korean Wood Science and Technology
• /
• 제24권2호
• /
• pp.20-25
• /
• 1996

Wood chips of oak(Quercus mongolica) and larch(Larix leptolepis) were exploded with the optimum condition. Main components of exploded wood were separated with hot hot water and methanol. The hemicelluloses were purified from hot water extracts and alditol complexs were prepared from purified hemicellulose. And also, cellulose nitrate was prepared from extractive residue and characterized. The results can be summarized as follows. 1. Amounts of carbohydrate(72~79%) in the crude hemicellulose of larch wood was more than those of oak wood(55~66%). 2. The crude hemicelluloses were mainly composed of oligosaccharides in oak wood but those in larch wood contained about 50% monosaccharides. 3. Decolorization of hemicellulose was successful with activated charcoal and ion-exchange resin treatment. The alditol yields were 56.3~82.9%. 4. The degree of substitution(D.S.) of cellulose nitrate was 1.95~2.87 and it showed a good acetone solubility.

• 한국식품과학회지
• /
• 제6권2호
• /
• pp.75-78
• /
• 1974

본(本) 실험(實驗)에서는 현재(現在)까지 학문적(學問的)으로 충분(充分)히 밝혀지고 있지 않은, 한우유(韓牛乳)의 이화학적(理化學的) 성질(性質)을 구명(究明)하기 위(爲)하여 한우유(韓牛乳)의 주성분(主成分)을 분석(分析)하고, 또한 DEAE-cellulose를 사용(使用)하여 산(酸) casein, 유청단백질(乳淸蛋白質)을 분별(分別)하여 다음과 같은 결과(結果)를 얻었다. 1. 한우유(韓牛乳)의 비중(比重)은 1.036, 산도(酸度) 0.21, pH는 6.4였고 알콜시험(試驗)에서는 정상(正常)이었다. 2. 한우유(韓牛乳)의 수분함량(水分含量)은 88.39%였고, 무지고형분(無脂固形分) 9.53%였고, 지방(脂肪)은 2.08%, 단백질(蛋白質)은 3.99%, 유당(乳糖)은 4.76%였고 Sialic acid는 0.25%였다. 3. 총단백질중(總蛋白質中) casein이 3.07% 유청단백질(乳淸蛋白質)이 1.13%, lactoglobulin 0.34%, lactalbumin은 0.66%였다. 4. 6M 요소(尿素)를 함유(含有)한 0.005M TCU-buffer를 사용(使用)하여 DEAE-cellulose column에 의(依)해서 한우유(韓牛乳)의 산(酸) casein을 분별(分別)한 결과(結果) 4개(個)의 fraction을 얻었다. 5. 0.04M phosphate-buffer를 사용(使用)하여 DEAE-cellulose column에서 유청단백질(乳淸蛋白質)을 분별(分別)한 결과(結果) 4개(個)의 fraction을 얻어 각(各) fraction의 면적(面積)을 냈다.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제6권2호
• /
• pp.89-94
• /
• 2001

The binding of cellobiohydrolases to cullulose is a crucial initial step in cellulose hydrolysis. In the search for a detailed understanding of the function of cellobiohydrolases, much information concerning how the enzymes and their constituent catalytic and cellulose-binding changes during hydrolysis is still needed. The adsorption of purified two cellobiohydrolases (Ce17A and Ce16A) from Trichoderma reesei cellulase to microcrystalline cellulose has been studied. Cellobiohydrolase II (Ce16A) does not affect the adsorption of cellobiohydrolase I (Ce17A) significantly, and there are specific binding sites for both Ce17A and Ce16A. The adsorption affinity and tightness of the cullulase binding domain (CBD) for Ce17A are larger than those of the CBD for Ce16A. The CBD for Ce17A binds more rapidly and tightly to Avicel than the CBD for Ce16A. The decrease in adsorption observed when the two cellobihydrolases are studied together would appear to be the result of competition for binding sites on the cellulose. Ce17A competes more efficiently for binding sites than Ce16A. Competition for binding sites is the dominating factor when the two enzymes are acting together, furthermore adsorption to sites specific for Ce17A and Ce16A, also contributes to the total adsorption.

• 농업과학연구
• /
• 제21권2호
• /
• pp.142-147
• /
• 1994

Carboxyrrethyl cellulose CM32 (Whatman Biochemical Ltd.)로 조제한 TNP-cellulose에 대하여 섬유소 분해효소의 활성도 측정을 위한 기질로서의 특성을 검토하였다. 섬유소 분해효소에 의한 TNP-cellulose의 가수분해는 Michaelis-Menten kinetics에 의하였으며, 그 분해의 위치가 amide결합이 아니고 섬유소 부분임을 확인하였다. 효소원이 다른 세가지 섬유소 분해효소 (Onozuka R-10 from Trichoderma viride; Cellulase II from Aspergillus niger; cell-free enzyme from Cellulomonas sp.)의 활성도를 TNP-cellulose를 기질로 하여 측정할때 그 반응조건을 기왕의 환원당 측정법과 비교해 보면: 반응 온도의 범위에는 변화가 없었으나, pH범위는 여러 효소에서 다소 넓어짐으로서 TNP-cellulose를 기질로 할때 수소이온의 영향을 적게 받음을 확인하였다. TNP-cellulose를 기질로 사용한 활성도 측정방법은: 세가지 효소 모두 일정 농도의 범위에서 활성도와 비례관계가 성립함으로서 효소원이 다른 여러 섬유소 분해효소에 적용할 수 있으며; 기왕의 DNSA법에 의한 환원당 측정법보다 감도가 높았고; 그 활성도의 값은 기왕의 환원당 측정법이나 점성도 측정법에 의한 결과와 대체로 비례적이었으나, 효소의 종류에 따라서 점성도 측정법의 결과와 반드시 일치하지는 않음으로서, 순수한 endo-효소의 활성도 측정을 위한 특이적인 방법이 되지 못함을 알수 있었다.

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 1988년도 학술발표초록집
• /
• pp.25-25
• /
• 1988

• Bulletin of the Korean Chemical Society
• /
• 제16권8호
• /
• pp.742-747
• /
• 1995