• 한국키틴키토산학회지
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• 제23권4호
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• pp.228-233
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• 2018

삼림 토양 시료를 이용하여 cellulase 생산균주를 단리한 결과, Carboxymethylcellulose (CM-cellulose)를 기질로 첨가한 고체배지상에서 명확한 활성환을 형성하는 총 6종류의 cellulase 생산균주를 단리하여, 단리한 균주 유래의 16S rDNA유전자 염기서열 분석을 통하여 균주 동정을 진행하였다. 그 결과 본 연구에서 단리된 균주는 Bacillus subtilis 4종류, Bacillus amyloliquefaciens 1종류, Bacillus cereus 1종류로 동정되었다. 이 중에서 CM-cellulose에 대한 가장 높은 cellulase 활성을 보이는 Bacillus subtilis를 선정하여 Bacillus subtilis NSC로 명명하였다. Bacillus subtilis NSC 유래 cellulase는 균주 배양 36~48시간에서 가장 높은 cellulase 생산성을 보였으며, 최적 pH 및 온도를 검토한 결과, 본 균주 유래 cellulase는 pH 5.0과 $40^{\circ}C$에서 가장 높은 효소 활성을 나타내었다. 그리고, pH 4.0~5.0 조건에서 30분간 효소처리를 하여도 효소활성의 감소가 없었으며, $40^{\circ}C$까지는 30분간의 열처리에도 효소활성의 저하 없이 안정한 특성을 보였다. CM-cellulose, Alkali swollen cellulose, Sigmacell-cellulose, Alpha-cellulose, 그리고 Avicel을 기질로 기질 특이성을 한 결과 CM-cellulose에 대하여 가장 높은 효소 활성을 나타내었으며, cellulose 결정구조를 보유하고 있지않는 CM-cellulose와 Alkali swollen cellulose에 대해서는 명확한 효소활성을 보였다. 하지만, cellulose 결정구조를 보유하고 있는 Sigmacell Cellulose, Alpha-cellulose, 그리고 Avicel 기질에 대해서는 CM-cellulose 활성의 각각 8%, 8%, 그리고 4%의 매우 낮은 효소활성을 나타내었다. Bacillus subtilis NSC 유래 cellulase의 0.26 U/ml 조효소액과 0.52 U/ml 조효소액을 이용하여 CM-cellulose의 분해 특성을 검토하였을 때 두 조효소액 모두 반응 CM-cellulose에 대해 반응 120분 후에 0.43 U/ml와 0.76 U/ml의 효소 활성을 나타내었다.

• Archives of Pharmacal Research
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• 제25권6호
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• pp.964-968
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• 2002

Colon drug delivery is advantageous in the treatment of colonic disease and oral delivery of drugs unstable or suceptible to enzymatic degradation in upper GI tract. In this study, multilayer coated system that is resistant to gastric and small intestinal conditions but can be easily degraded by colonic bacterial enzymes was designed to achieve effective colon delivery of prednisolone. Variously coated tablets containing prednisolone were fabricated using chitosan and cellulose acetate phthalate (CAP) as coating materials. Release aspects of prednisolone in simulated gastrointestinal fluid and rat colonic extracts (CERM) were investigated. Also, colonic bacterial degradation study of chitosan was performed in CERM. From these results, a three layer (CAP/Chitosan/CAP) coated system exhibited gastric and small intestinal resistance to the release of prednisolone in vitro most effectively. The rapid increase of prednisolone in CERM was revealed as due to the degradation of the chitosan membrane by bacterial enzymes. The designed system could be used potentially used as a carrier for colon delivery of prednisolone by regulating drug release in stomach and the small intestine.

• Journal of the Korean Wood Science and Technology
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• 제24권2호
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• pp.55-60
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• 1996

Tripitaka Koreana were made during Coryo Dynasty from 1236 to 1251 A.D. Buddhist scriptures were engraved on 81.340 wooden plates. Some plates were varnished with Rhus lacquer, but most of them were uncoated. Macroscopically, most of the plates appeared intact due to the storage in a well-ventilated wooden house. Because, they were irregularly used for printings with ink, it can be assumed that they were repeatedly exposed to ink-water and drying processes. The present were made to examine the changes of wood cell structures occurred during long-term aging deterioration processes in these dry archaeological wooden plates. Light, scanning and transmission electron microscopes were employed for this study. Wedge-shaped cracks and delamilations were found from the lumen side toward the compound middle lamellae and they progressed toward primary or secondary walls. A large amount of hypae in vessels and the degradation of vessel-ray pit walls by the fungal hyphae were observed. When compared to the recent wood, the birefringence of wood fibers was considerably lower or completly disappeared, suggesting the degradation of crystalline cellulose in these wood samples. The degradation of the cell wall could be also revealed the calculation of crystallinity with X-ray diffraction and the size of crystalline region was estimated.

• 펄프종이기술
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• 제35권3호
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• pp.74-78
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• 2003

The structural property of phenolic and non-phenolic lignin has an effect on the reaction rate of lignin by oxygen and chlorine dioxide respectively. Moreover, the undesirable degradation of cellulose followed by lignin degradation is influenced by chemical charge and reaction time. In this paper, several lignin model compounds were used to illuminate the interaction of oxygen and chlorine dioxide by varying the position of O and D(OD, DO, ODO and DOD), and gas chromatography method was used to investigate the degradation of lignin by determining the content of methoxyl groups in lignin. It was shown that structural properties of lignin models were more influential on the degradation and demethylation of lignin than the above combination. Combination of oxygen and chlorine dioxide, however, was more effective in degradation of lignin than only one stage, and three stages than two stages.

• Journal of the Korean Wood Science and Technology
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• 제40권4호
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• pp.229-236
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• 2012

본 연구는 감마선 조사가 소나무(Pinus densiflrora), 느티나무(Zelkovas serrenata), 오동나무(Paulownia tomentosa)의 세포벽 열화, 셀룰로오스 결정화도, 휨 강도에 미치는 영향을 구명하기 위해 수행되었다. 각 목재 시편들을 100 kGy 선량의 감마선 조사 후 주사전자현미경(scanning electron microscope; SEM) 관찰 결과, 목재 세포벽 열화는 관찰되지 않았으며 휨 강도 역시 현저한 변화가 나타나지 않았다. 감마선 조사에 의한 셀룰로오스 결정화도 역시 유의한 변화가 관찰되지 않았다. 이러한 감마선에 대한 목재의 높은 안전성은 감마선 조사 기술을 재질손상 없이 목재를 가해 중인 균류와 충류 구제를 위해 적용할 수 있음을 의미한다.

• Journal of Microbiology and Biotechnology
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• 제22권1호
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• pp.126-132
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• 2012

A cellulose-degrading composite microbial system containing a mixture of microbes was previously shown to demonstrate a high straw-degrading capacity. To estimate its potential utilization as an inoculant to accelerate straw biodegradation after returning straw to the field, two cellulose-degrading composite microbial systems named ADS3 and WSD5 were inoculated into wheat straw-amended soil in the laboratory. The microbial survival of the inoculant was confirmed by a denaturing gradient gel electrophoresis (DGGE) analysis, whereas the enhancement of straw degradation in soil was assessed by measuring the mineralization of the soil organic matter and the soil cellulase activity. The results indicated that most of the DGGE bands from ADS3 were detected after inoculation into straw-amended autoclaved soil, yet only certain bands from ADS3 and WSD5 were detected after inoculation into straw-amended non-autoclaved soil during five weeks of incubation; some bands were detected during the first two weeks after inoculation, and then disappeared in later stages. Organic matter mineralization was significantly higher in the soil inoculants ADS3 and WSD5 than in the uninoculated controls during the first week, yet the enhanced degradation did not persist during the subsequent incubation. Similar to the increase in soil organic matter, the cellulase activity also increased during the first week in the ADS3 and WSD5 treatments, yet decreased during the remainder of the incubation period. Thus, it was concluded that, although the survival and performance of the two inoculants did not persist in the soil, a significant enhancement of degradation was present during the early stage of incubation.

• 보존과학연구
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• 통권35호
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• pp.111-119
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• 2014

본 연구는 문화재를 가해하는 미생물을 분리하여 그 특성을 파악한 것이다. PDA 배지를 이용하여 목조문화재 동춘당으로부터 미생물을 분리 동정을 하였다. 기질분해 실험을 통해 19종의 미생물을 분리하였다. 미생물을 배양하면서 흡광도를 통해 성장곡선을 측정하였고, pH의 변화량도 측정하였다. 72시간 배양한 결과, 시간에 따라 미생물이 증가함을 확인하였고, pH도 미생물 증가에 따라 증가하는 것을 확인하였다. DNS 시약을 통해 cellulose 분해 정도를 측정한 결과에서는 45시간 이후 DNS 시약과 결합하여 반응을 나타내는 환원당이 급격히 감소하는 결과를 확인하였다. 분리된 Methylobacterium sp.는 cellulase를 분비하여 목재를 분해하는 것을 확인하였다.

• 미생물학회지
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• 제36권2호
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• pp.130-135
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• 2000

순천만 갯벌의 3개 지점의 표층(5cm)과 심층(20 cm)토양의 물리화학적 요인과 종속영양세균의 분포, 섬유소 분해율과 체외효소의 활성을 측정하였다. 온도, 수분함량, 인산염 인 그리고 유기물함량은 각각 -1~$30^{\circ}C$, 42.1~53.1%, 0.0779~0.1961mg/g, 그리고 1.99~7.64%로 나타나었다. 섬유소 films의 분해율은 7.7%~100%/month 범위로 1~2월에 최저 그리고 8~9월에 최고의 분해율을 나타냈다. 종속영양세균의 분포는 $0.87{\times}10^6 ~ 3.6{\times}10^7 $CUFs/g dry soil의 범위에 속해Tdmu 심층의 경우 표층에 비해 낮았다. MUF-기질의 분해율로 측정한 phoshatase, $\alpha$-D-gluocosidase, $\beta$-D-glucosidase, cellobiohydrolase 활성의 변화는 각각 152.23~1779.80 nMi/hr 2.67~202.18 nM/hr, 5.03~258.26 nM/hr, 3.42~63.07 nM/hr으로 모두 하계에 상대적으로 높은 값을 나타내었다. 섬유소 분해는 수온상승이 주된 요인이었으며, 정점간, 깊이간 큰 차이는 나타나지 않았다. 체외효소의 활성은 온도 및 섬유소 분해율과 높은 양의 상관관계를 나타냈다. 종속영양세균의 분포는 섬유소 분해와 체외효소의 활성과 높은 상괸은 나타나지 않았다.

• 한국안전학회지
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• 제9권2호
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• pp.12-17
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• 1994

Smoke evolved from burning cellulose insulation treated with boric acid-borax-alum as combustion retardants has been studied using a light absorption method. It has been shown that the quantity of smoke are decreased with the increase of oxygen concentration. Applied fire retardants did not increase smoke generation from investigated cellulose insulation in range of themal degradation without flaming. These same fire retardants increased from in the range of flaming combustion. The results of this work have been analysed using imperical equation, which correlated the smoke density at oxygen content of combustion transition. This equation may be. $\sigma$=$\sigma$$_{T}$ exp｛-7.24$\times$10$^{-7}$ ( $O_2$ $O_{2.T}$)｝Where $O_2$is the concentration of oxygen in the oxidizing gas, and $O_{2.T}$ refers to oxygen concentration of combustion transition.n.n.n.

• Molecules and Cells
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• 제28권4호
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• pp.369-373
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• 2009

Heterologous secretory expression of endoglucanase E (Clostridium thermocellum) and ${\beta}$-glucosidase 1 (Saccharomycopsis fibuligera) was achieved in Saccharomyces cerevisiae fermentation cultures as an ${\alpha}$-mating factor signal peptide fusion, based on the native enzyme coding sequence. Ethanol production depends on simultaneous saccharification of cellulose to glucose and fermentation of glucose to ethanol by a recombinant yeast strain as a microbial biocatalyst. Recombinant yeast strain expressing endoglucanase and ${\beta}$-glucosidase was able to produce ethanol from ${\beta}$-glucan, CMC and acid swollen cellulose. This indicates that the resultant yeast strain of this study acts efficiently as a whole cell biocatalyst.