• Journal of Microbiology and Biotechnology
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• 제22권4호
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• pp.462-469
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• 2012

A metagenomic fosmid library was constructed from genomic DNA isolated from the microbial community residing in hindguts of a wood-feeding higher termite (Microcerotermes sp.) collected in Thailand. The library was screened for clones expressing lignocellulolytic activities. Fourteen independent active clones (2 cellulases and 12 xylanases) were obtained by functional screening at pH 10.0. Analysis of shotgun-cloning and pyrosequencing data revealed six ORFs, which shared less than 59% identity and 73% similarity of their amino acid sequences with known cellulases and xylanases. Conserved domain analysis of these ORFs revealed a cellulase belonging to the glycoside hydrolase family 5, whereas the other five xylanases showed significant identity to diverse families including families 8, 10, and 11. Interestingly, one fosmid clone was isolated carrying three contiguous xylanase genes that may comprise a xylanosome operon. The enzymes with the highest activities at alkaline pH from the initial activity screening were characterized biochemically. These enzymes showed a broad range of enzyme activities from pH 5.0 to 10.0, with pH optimal of 8.0 retaining more than 70% of their respective activities at pH 9.0. The optimal temperatures of these enzymes ranged from $50^{\circ}C$ to $55^{\circ}C$. This study provides evidence for the diversity and function of lignocellulose-degrading enzymes in the termite gut microbial community, which could be of potential use for industrial processes such as pulp biobleaching and denim biostoning.

• 미생물학회지
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• 제17권1호
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• pp.42-48
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• 1979

Pemicillum chrysogenum의 건전균(PC)과 바이러스감염균(PCV)을 사용하여 cellulase의 존재여부와 그 활성 정도를 알아보기 위해 밀기울에 배양하여 효소액으로 만들어 균의 생장에 따른 배양액의 최적 pH와 최적 배양일 및 Na-CMC 기질액을 이용하여 효소액의 활성에 미치는 최적 pH, 온도, 및 효소농도를 알아보고자 본 실험에 착수하여 다음과 같은 결과를 얻었기에 이에 보고하는 바이다. 1) PC외 PCV균의 생장에 따른 배양액의 최적 pH는 균주 접종전 배지와 작은 pH6.4로 나타났다. 2) 최적 배양일은 최적 pH를 나타낸 배양6일이 가장 높은 활성을 나타냈고, PCV는 PC의 50%의 활성이었다. 3) PC균 배양 효소액이 기질과 반응시 효소활성이 가장 높은 최적 pH는 pH5.0으로 나타났고, PCV 균 배양 효소액에서는 pH 6.0으로 나타났다. 4) PC와 PCV균 배양효소액 모두 기질과 반응시 효소 활성이 가장 높은 최적 온도는 $50^{\circ}C$로나타났다. 이상의 결과에서 cellulase의 활성도는 PC건전균이 PCV감입균보다 높은 활성을 나타낸 것을 알 수 있었다.

• Journal of the Korean Wood Science and Technology
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• 제38권6호
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• pp.547-560
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• 2010

본 연구에서는 Schizophyllum commune의 당 분해효소 생산을 위한 최적 배양 조건과 목질바이오매스에 대한 당화 특성에 대하여 연구하였다. S. commune 균체 외 효소에는 endo-${\beta}$-1,4-glucanase (EG), cellobiohydrolase (CBH), ${\beta}$-glucosidase (BGL)와 같은 cellulase와 ${\beta}$-1,4-xylosidase (BXL)이 함유되어 있고 그 중에서 EG 및 BGL활성이 비교적 높은 활성을 나타낸 것으로 밝혀졌다. S. commune에서 생산된 EG, BGL, 및 CBH의 최적 온도는 $50^{\circ}C$이었으나, 열안정성을 가지는 온도범위는 $30{\sim}40^{\circ}C$였다. 그리고 최적 pH는 5.5이었으며 열 안정성을 나타내는 온도범위에서의 적정 pH는 동일한 pH 5.5이었다. Cellulase 생산을 위한 S. commune의 최적배양 조건은, 탄소원으로 천연 cellulose, 질소원으로는 corn steep, 또는 peptone/yeast extract 혼합물, 비타민은 첨가하지 않는 것이 cellulase 효소활성 증가에 적절한 것으로 밝혀졌다. 또한 탄소원의 최적 첨가 농도는 2% (w/w), 적정 배양 pH 및 온도는 5.5~6.0과 $25{\sim}30^{\circ}C$로 밝혀졌다. 본 연구에서 도출된 최적 배양 조건으로 S. commune를 배양시키고 40배로 농축한 결과, EG가 3670.5 U/$m{\ell}$, BGL과 CBH가 각각 631.9 U/$m{\ell}$, 398.5 U/$m{\ell}$, BXL이 15.2 U/$m{\ell}$로 매우 높은 효소 활성을 나타냈다. 동일한 효소의 Filter Paper Unit도 11 FPU/$m{\ell}$로 상당히 높았다. 최적배양조건에서 얻어진 S. commune 효소로 다양한 기질에 대해 당화 시험을 실행한 결과, 전처리를 하지 않은 공시 활엽수에 대하여 낮은 당화율을 나타냈으나 천연 cellulose (Aldrich, ~20 micron) 및 볏짚의 경우에는 각각 50.5% 및 33.1%의 높은 당화성능을 나타냈다. 이 같은 당화 수준은 동일 효소농도 (30 FPU/g, glucan)로 비교했을 때 Trichoderma reesei 유래 상용화 효소인 Celluclast 1.5L의 약 110% 수준을 나타냄으로써, 대량생산기술 개발과정을 통해 목질계 당화 효소로의 상용화 가능성이 높은 균주로 평가되었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권5호
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• pp.268-274
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• 2002

Enzymatic hydrolysis of waste office paper was evaluated using three commercial cellulases, Acremonium cellulase, Meicelase, and Cellulosin T2. Varying the enzyme loading from 1 to 10% (w/w) conversion of waste office paper to reducing sugar was investigated. The conversion increased with the increase in the enzyme loading: in the case of enzyme loading of 10% (w/w), Acremonium cellulase yielded 79%conversion of waste office paper, which was 17% higher compared to Meicelase, 13% higher than that of Cellulosin T2. Empirical model for the conversion (%) of waste office paper to re-ducing sugar (x) was derived from experimental results as follow, x = $kE^{m}t^{(aE+b)}$ where k, m, a, and b de-note empirical constants. E indicates initial enzyme concentration.

• 한국인쇄학회지
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• 제18권1호
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• pp.121-139
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• 2000

This study is to test the possibility of applying the low-molecular weighted waste cellulase, which is produced in the process of cellulase production, to paper making. After experimenting on high-crystallized non-wood fibers with beating catalyst. I got the result that the condition for the optimal effect is temperature 40~6$0^{\circ}C$, the time 90min to 120min, pH 5.0 to 6.0, the enzyme contents 0.3% and that the effect of beating such as slight reduction of fiver viscosity, increase of water retention value(WRV) and shortening of fiber length was increased with waste cellulase. Through this process, the density, folding endurance, tensile strength and burst strength of paper was remarkably increased, which is inferred to result from the increased flexibility of fiber by individual characteristics of non-wood fiber, which was high-crystallized by penetrated low-molecular weight cellulases in the fiber.

• 산업기술연구
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• 제36권
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• pp.33-37
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• 2016

Cellulose binding domains (CBDs) of cellulases are thought to assist in the hydrolysis of insoluble crystalline cellulose. To gain sufficient amount of CBDs, the self-cleavable intein tag was used for expression and purification of Trichoderma reesei cellobiohydrolase I CBD in E. coli. Synthetic CBD genes, CBD or linker-CBD were cloned into expression vector pTYB11. Recombinant CBDs were successfully purified by intein mediated purification with an affinity chitin-binding domain. The final yields of recombinant CBD and linker-CBD were 3.2 mg/L and 1.4 mg/L, respectively. The functional bindings of recombinant CBDs were confirmed by Avicel binding experiments. The simple and easy purification method using self-cleavable intein tag can be further used in pretreatment of crystalline cellulose or characterization of engineered CBDs.

• Asian-Australasian Journal of Animal Sciences
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• 제12권1호
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• pp.104-112
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• 1999

Since the anaerobic rumen fungi were discovered in the rumen of a sheep over two decades ago, they have been reported in a wide range of herbivores fud on high fibre diets. The extensive colonisation and degradation of fibrous plant tissues by the fungi suggest that they have a role in fibre digestion. All rumen fungi studied so far are fibrolytic. They produce a range of hydrolytic enzymes, which include the cellulases, hemicellulases, pectinases and phenolic acid esterases, to enable them to invade and degrade the lignocellulosic plant tissues. Although rumen fungi may not seem to be essential to general rumen function since they may be absent in animals fed on low fibre diets, they, nevertheless, could contribute to the digestion of high-fibre poor-quality forages.

• Journal of Microbiology and Biotechnology
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• 제27권4호
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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.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.198-201
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• 2008

The electron beam irradiation was applied as a pretreatment of the enzymatic hydrolysis of yellow poplar with doses of 0$\sim$450 kGy. The higher irradiation dose resulted in the more degradation of hardwood biomass not only from carbohydrates but also from lignin. This changes originated from the irradiation resulted in the better response to enzymatic hydrolysis with commercial cellulases (Celluclast 1.5L and Novozym 342). The more improvement on enzymatic hydrolysis by the irradiation was found in the xylan than in the cellulose of yellow poplar.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.225-228
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• 2008

This study shows that lignocellulosic biomass saccharification work has been carried out with rice-straw by the extracellular enzyme from KMU001, and the enzymes produced in 5%(w/v) wood biomass were characterized by protein and various enzyme activity measurements. Several cellulases such as Endoglucanase(EG), $\beta$-D-1,4-Glucosidase(BGL), Cellobiohydrolase(CBH), and $\beta$-D-1,4-Xylanase (BXL) were detected. Saccharification of rice-straw by the enzyme yielded about 233mg/g of glucose after 48hrs.