• 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.

• Journal of Ginseng Research
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• 제6권2호
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• pp.131-137
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• 1982

The effect of red ginseng residue on the several enzyme activities of the koji and alcohol fermentation were investigated. The koji showed maximum values of amylase and cellulase activity when it was prepared by 30% red ginseng residue and 70% wheat bran, and of protease activity when it was prepared by 40% red ginseng residue and 60% wheat bran-${\alpha}$ amylase activity of the koji during its fermentation was increased rapidly until 4 days and there after it was increased slowly, but ${\beta}$-amylase was rapidly increased after 3 days fermentation. During the preparation of the koji, the acidic, neutral protease and cellulase activities showed the maximum value after 3 days fermentation and the alkaline protease showed the maximum value within 4-6 days fermentation. On the otherhand, fermented broth, containing 6%(v/v) alcohol, could be obtained when the substrate was saccharified by the koji, based on 25% red ginseng residue and 75% wheat bran, prior to alcohol fermentation.

• Journal of the Korean Wood Science and Technology
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• 제15권4호
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• pp.18-25
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• 1987

섬유성 물질을 자화(資化)하는 미생물을 자연계로 부터 분리하여 효소생산 및 당화조건을 검토하였다. 분리 균주 256주 중 효소생산에 가장 유효하다고 인정되는 Aspergillus fumigatus KC-1을 우수 균주로 선발하였다. 본 균은 alkaline peroxide로 전처리한 현사시 목분 1%를 탄소원으로하여 $45^{\circ}C$에서 진탕 배양시 4~5일째 효소생성(여지, Avicel, 탈지면, CMC, Salicine 및 Xylan 당화활성)이 최고치에 달했다. 효소의 최적 pH는 4.5, 최적온도는 $60^{\circ}C$였다. 본 균의 효소에 의한 현사시 목분의 가수 분해시 1 % NaOH와 20% 과초산으로 탈리그닌한 목분의 가수 분해율이 가장 높았고, 최종 산물로 glucose와 약간의 cellobiose 및 xylose가 검출되었다. 따라서 본균의 cellulase는 cellulose를 쉽게 glucose로 당화하는데 매우 유효한 효소로 판단되었다. 현사시 목분의 효소분해에 대한 탈리그닌 정도, 기질의 크기 및 농도의 영향도 아울러 검토하였다.

• 미생물학회지
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• 제18권2호
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• pp.51-58
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• 1980

Mutational experiments were performed to improved to improve the protease productivity of Aspergillus flavus KU 153, which is selected among the wild strains. A UV-induced mutant strain having high protease productivity was obtained by the use of the clear zone method as a simple criterion for a primary screening test. Neutral and alkaline protease activities of hte mutant strain were higher than 1.8 times, comopared with those of the parental strain, respectively, while in the case of acid protease, it was 2.7 times. The mutant strain selected was more powerful in the production of cellulase and amylase, as well s protease in wheat bran, compared with those of the parental strain. protease production of the parental strain has reached maximum level at 3 days culture, while alkaline nad neutral protease production of the mutantstrain has reached at 2 days culture. On the other hand, the mutant strain formed the spore slowly, compared with the parental strain. Column chromatography of the neutral protease on DEAE-Sephadex A-50 showed that the mutant strain was not induced the formation of another neutral protease isozyme, but induced the variation in the function of regulatory gene.

• 한국미생물·생명공학회지
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• 제16권3호
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• pp.213-218
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• 1988

섬유소 폐기물인 볏짚으로부터 butanol를 생산하기 위하여 Clostridium acetobutylicum KCTC1037 와 cellulase(from Trichoderma viride)을 발효액에 동시에 첨가하여 발효시키는 동시당화 발효법(Simultaneous saccharification and fermentation, SSF)을 수행하였다. Alkali 처리한 볏짚을 발효기질로 사용한 결과 그 농도를 25%로 사용하였을 때 최고 150mM의 butanol이 생산되었고, 15% 볏짚을 사용하였을 때는 97mM의 butanol이 생산되었다. 그러나 ball milled 볏짚의 경우 발효산물 중 대부분이 acetate와 butyrate로 주로 산이 생산되었으며 따라서 solventogenesis는 거의 일어나지 않았다. 또한 그 농도별 실험에서 보면 8%의 ball milled 볏짚 사용시 66mM의 butanol이 생산된 반면 그 이상의 농도에서는 butanol 생산량이 점차 감소하는 추세를 보였으며 acetate, butyrate 같은 산은 계속 증가 추세를 보였다. 이것으로 보아 ball milled 볏짚에는 butanol 발효 과정 중 acidogenesis에 서 solventogenesis로의 전이 (shift)를 방해하는 어떤 인자가 있으리라고 추측되었으며 alkali 처리방법에 의해서 이 방해자는 제거될 수 있는 것으로 관찰되었다.

• 미생물학회지
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• 제42권1호
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• pp.67-72
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• 2006

클로닝된 Bacillus circulans ATCC21367 유래 cellulolytic xylanase 유전자(bglBC2)의 염기서열을 결정 분석하였다. 본 유전자는 1,224 bp의 407개 아미노산을 암호하는 open reading frame (ORF)으로 구성되어 있었으며 염기서열로부터 산출된 유전자의 분자량은 45 kDa으로 효소의 SDS-PAGE로부터 측정된 분자량과 일치하였다. ATG 개시 코돈의 9bp 위쪽에 Shine-Dalgarno (SD) 서열로 추정되는 5'-AAAGGAG-3' 서열이 확인되었고 그 상단에 promoter로 추정되는 -35 서열(TTTACA)과 -10 서열(TATACT)이 위치하고 있었으며, 이는 B. subtilis promoter consensus sequence와 유사하였다. 한편, 이 효소의 아미노산 서열은 이미 보고된 B. circulans KSM-N257의 alkaline $endo-\beta-1,4-glucanase$와는 97%, B. circulans WL-12의 $endo-\beta-1,3-1,4-glucanase$와는 75%, Bacillus sp. KSM-330의 $endo-\beta-1,4-glucanase$ (cellulase)와는 45%의 유사성을 나타내었다. 또한 bglBCS 염기서 열의 정보를 GenBank에 등록하였으며 등록번호는 Ar269256이다.

• 농업과학연구
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• 제25권1호
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• pp.124-130
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• 1998

알칼리성 cellulase를 분비하는 세균을 토양으로 부터 분리하고 그 중 알칼리 환경하에서 생육이 양호하며 CMCase 생성능이 우수한 균주 AC-711를 선발하였다. AC-711 균주의 형태적, 배양적 및 생리학적 특성을 조사한 결과 호알칼리성 Pseudomonas속의 균주로 동정되었으나 염색체 DNA의 G+C함량이 54.43 mol%로서 Pseudomonas속보다 다소 낮은 값이었으며, 세포벽 지방산의 주성분은 15:0 anteiso 및 17:0 anteiso이었다. AC-711 균주의 생육은 $25{\sim}37^{\circ}C$, pH 9.5~10.5에서 좋았으며 효소생산을 위한 최적 조건은 $30^{\circ}C$, pH 10.3 이었다. 또한 효소생산을 위한 배지조성은 $KH_2PO_4$ 0.1%, $CoCl_2$ 0.02%, Tween 80 0.02%, $Na_2CO_3$ 0.5%에 탄소원으로서 CMC 1%, 질소원으로서 yeast extract 0.8%를 사용하였을 때가 가장 좋았다. CMCase의 생산은 3일 배양후 가장 높았으며, 생성된 효소는 filter paer와 avicel과 같은 결정성 섬유소보다는 수용성 섬유소인 CMC에 대한 분해 활성이 현저히 높아서 세제 첨가제로서의 이용 가능성이 주목되었다.

• 미생물학회지
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• 제46권1호
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• pp.68-72
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• 2010

Bacillus licheniformis B1의 ${\beta}$-1,4-glucanase 유전자는 Escherichia coli BL21에서 발현되어, 이로부터 수용성의 50 kDa 단백질이 과량생산되었다. 반면에 B. licheniformis에서는 37 kDa의 형태가 분비되었다. E. coli에서 발현된 ${\beta}$-1,4-glucanase는 leader peptide가 제거되지 않고 포함되어 있고 Bacillus에서는 효소의 carboxy 말단에서 processing이 일어난 것으로 보인다. E. coli에서 생산된 ${\beta}$-1,4-glucanase의 최적온도는 $40^{\circ}C$이었지만, $60^{\circ}C$에서도 최대치의 76% 활성을 유지하였다. 효소의 최적 pH는 7이었고, 효소의 활성은 전체적으로 보면 약산성, 중성 및 약알칼리 영역에 널리 걸쳐 있었다. Cellulase는 식품, 세제, 펄프, 제지, 섬유산업 등 다양한 분야에서 주로 산성의 곰팡이계 효소가 이용되고 있으나, 중성 및 알칼리성 cellulase 연구 및 개발은 미흡한 편이다. 본 연구에서 개발된 중성 cellulase가 바이오 연료 개발 등의 분야에서 활용되기를 기대해 본다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권10호
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• pp.1540-1547
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• 2019

Objective: This study was conducted to evaluate the effects of tannins and cellulase on growth performance, nutrient digestibility, blood profiles, intestinal morphology, and carcass characteristics in Hu sheep. Methods: A total of 48 three-month-old meat Hu sheep ($25.05{\pm}0.9kg$) were blocked based on body weight, and randomly allotted to 4 treatments with 3 replicates of 4 sheep each. The experiment lasted for 80 d, and dietary treatments were as follows: i) CON, control diet; ii) TAN, CON+0.1% tannins; iii) CEL, CON+0.1% cellulase; iv) TAN+CEL, CON+0.1% tannins and 0.1% cellulase. Results: Compared with CON, CEL, and TAN+CEL had greater (p<0.05) final body weight (FBW) and average daily gain but lower (p<0.05) feed conversion ratio, while FBW of TAN+CEL was lower (p<0.05) than that of CEL. The apparent total tract digestibility (ATTD) of dry matter in TAN, CEL, and TAN+CEL groups were higher (p<0.05) than that in CON. CEL and TAN+CEL groups had greater (p<0.05) ATTD of crude fiber compared with TAN and CON, while TAN group had lower (p<0.05) ATTD of crude protein than other treatments. TAN, CEL, and TAN+CEL groups increased (p<0.05) serum globulin and alkaline phosphatase but decreased (p<0.05) albumin/globulin. Serum total protein was greatest for TAN+CEL, intermediate for TAN and CEL and least for CON (p<0.05). TAN+CEL group increased (p<0.05) dressing percentage compared with CON, while the backfat thickness of CEL was lower (p<0.05) than that of CON. The villus height of jejunum and ileum in CEL and TAN+CEL groups were greater (p<0.05) than that in CON, and the crypt depth and villus height: crypt depth of jejunum were increased (p<0.05) in TAN, CEL, and TAN+CEL groups. Conclusion: The addition of tannins and cellulase together promoted nutrient digestion, liver protein synthesis and intestinal development and thus improved growth performance and carcass characteristics.

• Journal of Microbiology and Biotechnology
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• 제19권9호
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• pp.873-880
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• 2009

A novel xylanase gene, Kxyn, was cloned from Kocuria sp. Mn22, a bacteria isolated from the deep sea of the east Pacific. Kxyn consists of 1,170 bp and encodes a protein of 390 amino acids that shows the highest identity (63%) with a xylanase from Thermohifida fusca YX. The mature protein with a molecular mass of approximately 40 kDa was expressed in Escherichia coli BL21 (DE3). The recombinant Kxyn displayed its maximum activity at $55^{\circ}C$ and at pH 8.5. The $K_m,\;V_{max}$, and $k_{cat}$ values of Kxyn for birchwood xylan were 5.4 mg/ml, $272{\mu}mol/min{\cdot}mg$, and 185.1/s, respectively. Kxyn hydrolyzed birchwood xylan to produce xylobiose and xylotriose as the predominant products. The activity of Kxyn was not affected by $Ca^{2+},\;Mg^{2+},\;Na^+,\;K^+$, ${\beta}$-mercaptoethanol, DTT, or SDS, but was strongly inhibited by $Hg^{2+},\;Cu^{2+},Zn^{2+}$, and $Pb^{2+}$. It was stable over a wide pH range, retaining more than 80% activity after overnight incubation at pH 7.5-12. Kxyn is a cellulase-free xylanase. Therefore, these properties make it a candidate for various industrial applications.