• Journal of Microbiology and Biotechnology
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• 제23권11호
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• pp.1577-1585
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• 2013

Bioethanol production from lignocellulose is considered as a sustainable biofuel supply. However, the low cellulose hydrolysis efficiency limits the cellulosic ethanol production. The cellulase is strongly inhibited by the major end product cellobiose, which can be relieved by the addition of ${\beta}$-glucosidase. In this study, three ${\beta}$-glucosidases from different organisms were respectively expressed in Saccharomyces cerevisiae and the ${\beta}$-glucosidase from Saccharomycopsis fibuligera showed the best activity (5.2 U/ml). The recombinant strain with S. fibuligera ${\beta}$-glucosidase could metabolize cellobiose with a specific growth rate similar to the control strain in glucose. This recombinant strain showed higher hydrolysis efficiency in the cellulose simultaneous saccharification and fermentation, when using the Trichoderma reesei cellulase, which is short of the ${\beta}$-glucosidase activity. The final ethanol concentration was 110% (using Avicel) and 89% (using acid-pretreated corncob) higher than the control strain. These results demonstrated the effect of ${\beta}$-glucosidase secretion in the recombinant S. cerevisiae for enhancing cellulosic ethanol conversion.

• 한국의류학회지
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• 제25권1호
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• pp.115-123
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• 2001

This paper discussed the assessment of hand of cotton fabrics by enzymatic hydrolysis. The subjective hand and preference of denim fabrics finished by enzymatic hydrolysis were evaluated using the scale developed. The factors affecting consumers taste for denim fabrics were analyzed by the statistical technique. The effects of enzymatic hydrolysis on the properties of cotton fabrics were also evaluated by subjective hand measurements. The results are as follow; As the weight loss increased, evaluators thought that fabrics become finer, smoother, softer, warmer and more refined, and the sense of durability is sleeker and weaker, and the sense of weight is more flexible, flossier, lighter, softer, thinner. They didnt catch the change of moisture related properties according to the rate of weight loss. They also thought fabrics became more elastic, and less wrinklier as the weight loss increased. As the weight loss increased, the fabric was more preferred. The limited weight loss which changes the preference from \"dislike\" to \"like\" was 12.87%. The most preferred fabric was that with 12.87% of weight loss. It is supposed that the preference of fabric was related to the terms such as \"sum-se-ha-da\"(섬세하다), \"mai-ku-rup-da\"(매끄럽다), \"yoo-yon-ha-da\"(유연하다), \"too-bak-ji-an-da\"(투박하지 않다), \"chom-chom-ha-da\"(촘촘하다), \"gil-ki-da\"(질기다), \"kun-juk-goe-ri-ji-an-da\"(끈적거리지 않다), \"ku-kim-i-ka-ji-an-nun-da\"(구김이 가지 않는다).

• 대한화학회지
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• 제22권3호
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• pp.164-172
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• 1978

상온에서 카르복시펩티다제 A에 의한 에스테르 기질의 가수분해 반응을 여러가지 외부 시약의 존재하에 행하였다. 산무수물 형태의 아실-효소중간체가 외부시약에 의해 공격받는다면 아실 부분에 포획된 생성물이나 효소부분에 포획된 생성물이 형성될 것이다. 반응생성물의 분광도와 효소활성도의 변화를 조사한 결과 포획반응의 생성물은 검출되지 않았다. 또한, O-(o-hydroxyphenylacetyl)-L-${\beta}$-phenyllactate가수분해에 대한 효소 반응속도변수를 측정하였다. 이 기질의 o-히드록시기가 분자내 포획기로서 작용하여 산무수물형태의 아실-효소중간체를 공격하여 20coumaranone이 형성되었나를 조사하였으나 분자내 포획반응이 일어났다는 증거는 얻지 못하였다. 이러한 중간체 포획반응의 실패는 포획용 시약이 아실-효소 중간체의 무수산기에 접근할때 입체적 방해를 받거나 중간체의 가수분해 단계도 효소에 의해 촉매되기 때문이라고 생각된다.

• Preventive Nutrition and Food Science
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• 제7권2호
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• pp.174-178
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• 2002

The influence of physical forms of gelatinized rice products on enzymatic hydrolysis in vitro and glycemic and insulinemic responses in normal subjects were studied. Densities of garaedu, bagsulgi, and cooked rice were 1.20, 1.18 and 1.11 g/mL, respectively, while moisture contents of garaeduk, bagsulgi, and cooked rice were 47.5, 43.1 and 66.0% (wt.), respectively. The highest initial rate of in vitro hydrolysis by porcine pancreatic $\alpha$-amylase was observed in bagsulgi followed by cooked rice and garaeduk. However, time for complete hydrolysis seemed to reach a plateau value. Postprandial glucose and insulin responses and satiety of rice products were studied in 12 normal subjects (mean age 23.2 $\pm$ 2.4 years, 6 men and 6 women). Postprandial serum glucose and insulin levels, after consumption of the rice products, reached a peak at 30 min. Garaeduk showed significantly less incremental responses for glucose (1627.5$\pm$134.9 mg.min/dL) and insulin (2041$\pm$287.0 uU.min/mL) than did bagsulgi for glucose (2407.4$\pm$208.3 mg.min/dL) and insulin (3582$\pm$264.4 uU.min/mL). Satiety responses to the rice products were not significantly different. Therefore, it can be concluded that garaeduk may be more beneficial in controlling postprandial hyperglycemia and hyperinsulinemia than bagsulgi. These results also suggest that physical properties of starch products, acquired by the specific processing methods, affect postprandial metabolism of carbohydrate foods.

• 한국식품과학회지
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• 제17권2호
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• pp.60-64
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• 1985

미생물에서 추출된 lipase를 유지방분해에 이용하기 위한 기초연구로서 Rhizopus delemar, Mucor sp. 및 Candida cylindracea에서 추출된 3중의 lipases를 유지방분해에 적합한 반응조건을 설정하고, 이들의 반응 특이성을 연구한 결과는 다음과 같다. 최적온도 및 최적pH는 Rhizopus delemar lipases가 $45^{\circ}C$, pH5.6 Mucor sp. lipases가 $35^{\circ}C$, pH7.5였으며, Candida cylindracea lipase는 $35^{\circ}C$, pH 7.0 이었다. 유지방에 대한 적정효소농도는 3종의 lipase 모두 $600{\sim}800\;units/ml$였다. 적정기질농도는 효소의 종류에 관계없이 유지방함량 20%였으며, 이들의 Km값은 R. delemar lipase가 6.06%, M sp. lipase가 7.69%, Can. cylindracea lipase가 7.99%였다. 반응시간에 따른 반응율을 조사한 결과 R. delemar lipase, M. sp. lipase, Can. cylindracea lipase순으로 높았으며 반응시간이 진행됨에 따라 저급지방산의 분해율이 높아졌으며, 반응 8시간에서는 R. delemar lipase는 butylic acid, M. sp. lipase는 palmitic acid, Can. cylindracea lipase는 Capric acid의 함량이 높았다.

• 패션비즈니스
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• 제13권2호
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• pp.78-86
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• 2009

When scouring and contraction finishing at $90^{\circ}C$ using Relaxer or Rotary Washer contraction and weight loss ratio in warp and weft directions were excellent. Also surface state of fabric after drying or sanding treatment was excellent without crease. Low melting polyester fabric showed a complete melting bond by heat setting(P/S) at above $160^{\circ}C$. The alkali hydrolysis reaction of polyester showed the breakpoint in the weight loss behavior test, polyester yarn showed a breakpoint ranging from 25% to 28%. This is due to the difference of the hydrolysis rate between regular polyester and soluble polyester. Initially the soluble polyester was eluted and micro-fibrillized 5 times faster than a regular polyester. At a later time, a regular polyester was reduced weight to impart a proper flexibility and drape property to the fabric. As a result of surface sanding finishing, the surface of interior fabric showed a surface state most stabilized when using Mesh No. 220 in mono 0.2d after elution finishing. When the rotation direction of sanding roller was pro-, pro-, pro-, and retro-direction, a directional effect of tuft was not shown, a writing effect as suede was exhibited and a surface state was even. Sublimation fastness was 3-4 class for polyester and 2-4 class for nylon. Light fastness 3-4 class after lapse of 100 hours and 2-4 class after lapse of 160 hours. Abrasion fastness was 3-4 class on wet and 4-5 class on dry Laundry fastness was 2-4 class. As such, the abrasion fastness is slightly reduced upon wetting and the use thereof for interior is excellent, whereas laundry fastness is slightly lowered.

• 한국식품과학회지
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• 제26권4호
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• pp.475-478
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• 1994

식품에 사용되는 화학적 변성전분류와 acetyl화 전분이 사용된 라면의 돼지 췌장 ${\alpha}-amylase$에 의한 in vitro 소화율($37^{\circ}C$에서 6시간)을 비교하였다. Native potato starch와 acetylated potato starch의 가수분해율은 각각 64.5%와 59.3%, native와 hydroxypropylated corn starch는 70.5%와 60.4%, 그리고 native와 hydroxypropylated high amylose corn starch는 65.2%와 57.3%로서 native한 것들이 유도체들보다 높았다. Waxy corn starch들의 소화율은 pregelatinized(74.3%)>native(72.1%)>acetylated(66.5%)>acetyl distarch adipate(56.4%)>hydroxypropyl distarch phosphate(50.7%)의 순으로 감소하였다. 국내에서 생산, 판매되고 있는 5개 회사의 봉지라면과 용기라면에 대한 실험에서는 실제 조리조건에서 소화율에 유의적 차이를 보이지 않았다. 결론적으로 화학적 변성전분의 소화율은 천연전분보다 낮지만 상용식품에서의 사용량이 매우 낮으므로 식품 섭취에 따른 전분질의 소화율에는 큰 영향을 미치지 않을 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제6권6호
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• pp.432-438
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• 1996

Native crystalline chitin was hydrolyzed in an agitated bead reaction system using crude chitinase excreted from Aspergillus fumigatus JC-19. The reaction was enhanced significantly, and the concentration and yield of reducing sugar after 48 hours were measured to be 35.42 g/I (w/v) and 0.64, respectively, around 1.86 times higher than those of the conventional system that was carried out without glass beads. The effect of reaction conditions, such as the amounts of chitin, chitinase and glass beads, and the size of glass bead, were examined. Ball milled chitin was also hydrolyzed in the agitated bead reaction system, the conversion yield and reaction rate of ball milled chitin for 24 hours increased up to 0.87 and 48.02 g/I, respectively. Chitinase showed relatively high stability in the agitated bead reaction system, particularly in the presence of enzyme stabilizer, $Ca^{++}$, which played a critical role in preventing the deactivation of chitinase by the physical impact of glass beads. The variations of the structural features of chitin during the reaction were followed by SEM and X-ray diffraction, and the enhanced hydrolysis reaction was caused by both the fragmentation of chitin particles and the destruction of the crystalline structure owing to the synergic effects of the attrition of glass beads and the hydrolytic action of chitinase.

• 약학회지
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• 제40권3호
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• pp.279-292
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• 1996

To assess their stability as a prodrug of 5-fluorouracil (5-FU), four N-acyloxycarbonyl derivatives (1-(N-tert-butyloxycarbonyl)glycyloxymethyl-5-FU :BGFU, 1-(N-tert-butyloxycar bonyl)-leucyloxymethyl-5-FU:BLFU, 1-(N-tert-carbobenzyloxymethyl) glycyloxymethyl-5-FU:CGFU and 1-(N-tert-carbobenzlyoxymethyl)leucyloxymethyl-5-FU:CLFU) possessing differently protected amino acids, and two acetic acid derivatives (5FU-1-acetylpentane:FUAP and 5-FU-1-acetylhexane:FUAH) were synthesized and their physicochemical properties, hydrolysis kinetics, acute toxicity and antitumor activity were evaluated. The lipid-water partition coefficients of six 5-FU prodrugs were higher than that of 5-FU and their aqueous solubilities were in the following rank order; BGFU>FUAP>CGFU>BLFU>CLFU${\simeq}$FUAH. The hydrolysis of N-acyloxycarboyl derivatives, greater at higher pH, was enhanced in presence of liver homogenate or human plasma. Meanwhile, acetic acid ester derivatives, very stable, were hydrolyzed by liver homogenate. Absorption rate constants were 0.181, 0.121, 0.111, 0.168, 0.168, 0.116 and 0.125 $hr^{-1}$ for 5-FU, BGFU, BLFU, CGFU, CLFU, FUAP and FUAH, respectively. The cytotoxicity of N-acyloxycarbonyl derivatives was 4 to 5 times lower than that of 5-FU, but that of acetic acid ester derivatives was negligeble. The $LD_{50}$ values were 204, 325.97 (133.59, amount as 5-FU), 708.16 (262.13), 663.50 (211.77), 382.33 (192.54) and 272.33 (130.09) mg/kg for 5-FU, BGFU, CGFU, CLFU, FUAP and FUAH, respectively. While N-acyloxycarbonyl derivatives showed enhanced antitumor activity and therapeutic ratio (3.30, 3.06, 4.19, 3.11 and 1.81 for BGFU, BLFU, CGFU, CLFU and 5-FU, respectively), FUAH and FUAP showed a smaller therapeutic ratio (0.79 and 0.83).

• 대한화학회지
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• 제40권4호
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• pp.254-263
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• 1996

두 자리 또는 세 자리의 질소 리간드를 갖는 5종류의 코발트(III) 착물을 합성하였다. 이 착물들의 촉매 작용을 질소의 위치가 다른 세 종류의 기질, 즉 P-Nitrophenyl Picolinate, P-Nitrophenyl nicotinate, 및 P-Nitrophenyl isonicotinate의 가수분해 반응에 대하여 자외선 분광법으로 측정하였다. 이 세 가지 기질 중에서 P-Nitrophenyl Picolinate가 촉매에 가장 민감한 반응을 보였으며, 이 화합물의 가수분해 반응은 pquohydroxo형태의 착물이 가장 많이 존재하는 pH 6.5에서 이 촉매들에 의하여 21-40배 촉진 되었다. P-Nitrophenyl Picolinate의 가수분해 반응에 대한 착물의 효과는 $Co(ibpn)(OH)>Co(aepn)(OH)_2(OH_2)>Co(tn)_2(OH)(OH_2)>Co(bpy)_2(OH)(OH_2)>Co(dien)(OH)_2(OH_2)$와 같이 나타났으며 이 가수 분해 반응은 분자내 일반 염기성 촉매 반응이 우세한 과정을 따르며 부분적으로 분자내 친핵성 촉매반응 메카니즘을 따르고 있음을 알 수 있었다.