• Journal of Microbiology and Biotechnology
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• 제6권3호
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• pp.173-178
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• 1996

Synergic effects among endo-xylanase, $\beta$-xylosidase, and acetyl xylan esterase of Bacillus stearothermophilus in the hydrolysis of xylan were studied by using birchwood, oat spelt, and acetylated xylan as substrates. Synergism between endo-xylanase and $\beta$-xylosidase was observed on all three substrates tested, indicating that $\beta$-xylosidase enhanced the production of xylose by relieving the end-product inhibition upon endo-xylanase conferred by xylooligomers. Endo-xylanase and $\beta$-xylosidase also showed synergism with acetyl xylan esterase in the hydrolysis of birchwood and acetylated xylan, while no synergic effect was detected in oat spelt xylan hydrolysis. Thus, the hydrolysis of xylan containing acetic acid side chains required the action of acetyl xylan esterase, which eliminated the steric hindrance of the side chains, leading to the better hydrolysis by endo-xylanase and $\beta$-xylosidase , and the acetyl xylan esterase activity was also enhanced by endo-xylanase and $\beta$-xylosidase for the latter enzymes provided acetyl xylan esterase with shorter xylan oligomers, the better substrate for the enzyme.

• Journal of Microbiology and Biotechnology
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• 제6권3호
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• pp.179-183
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• 1996

Synergism among endo-xylanase, $\beta$-xylosidase, and $\alpha$-L-arabinofuranosidase from Bacillus stearothermophilus upon xylan hydrolysis was investigated by using birchwood, oat spelt, and arabinoxylan as substrates. Endo-xylanase and $\beta$-xylosidase showed the cooperative action on all three substrates tested, revealing the fact that $\beta$-xylosidase assists endo-xylanase action in xylan hydrolysis by relieving the endproduct inhibition upon endo-xylanase conferred by xylooligomers. $\alpha$-L-Arabinofuranosidase also exhibited synergic effects with endo-xylanase and $\beta$-xylosidase on oat spelt and arabinoxylan, which contained significant amounts of arabinose side chains, whereas no synergism was detected on birchwood xylan which had only trace amounts of the side chain. Thus, the hydrolysis of xylan containing arabinose side chains required $\alpha$-L-arabinofuranosidase as well as endo-xylanase and $\beta$-xylosidase for the better hydrolysis of the substrates, and these enzymes work cooperatively in order to maximize the extent and rate of xylan hydrolysis.

• BMB Reports
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• 제28권4호
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• pp.348-352
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• 1995

A thermophilic Bacillus sp. strain KK-1 isolated from soil produced an extracellular xylanase. From the culture supernatant of Bacillus sp., the xylanase was purified to homogeneity by ammonium sulfate precipitation and DEAE-Sephadex A-50 chromatography. The molecular weight of the purified xylanase was estimated to be 45 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel permeation chromatography. The apparent $K_m$ values for xylanase, using oat spelt xylan and birchwood xylan as substrates, were 7.1 mg/ml and 3.2 mg/ml, and $V_{max}$ values were $27.0\;{\mu}mol{\cdot}min^{-1}{\cdot}mg^{-1}$ and $29.0\;{\mu}mol{\cdot}min^{-1}{\cdot}mg^{-1}$, respectively. The xylanase hydrolyzed oat spelt xylan to mostly xylobiose, xylotriose, and xylose. The amino acid composition indicated that the xylanase contained high amounts of amino add residues of glutamic acid and glutamine (Glx) and aspartic acid and asparagine (Asx).

• Journal of Microbiology
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• 제33권2호
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• pp.109-114
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• 1995

Alkalophilic Cephalosporium sp. RYM-202 produced multiple xylanases extracellularly. One of these xylanases was purified to electrophoretical homogeneity by chromatography with DEAE-Sephadex A-50, Sephacryl S-200 HR and Superose 12 HR. The purified xylanase differed from most other microbial xylanases in that it had low-molecular weight and acidic isoelectric point. The molecular weight of the xylanase in that it had low-molecular weight and acidic isoelectric point. The molecular weight of the xylanase was 23 kDa by SDS-polyacrylamide electrophoresis and 24 kDa by gel permeation chromatography, and the isoelectric point was 4.3. The xylanase had the highest activity permentation chromatography, and the isoelectric point was 4.3. The xylanase had the highest activity permeation chromatography, and the isoelectric point was 4.3. The xylanase had the highest activity at pH 8.0 and 50 .deg.C. It was stable over a wide range of pH and retained more than 80% of its original activity after 24 h of incubation even at pH 12. The Km values of this enzyme on birchwood xylan and oat spelts xylan were 2.33 and 3.45 mg/ml, respectively. The complete inhibition of the enzyme of n-bromosuccinimide suggests the involvement of tryptophan in the active site. The sylanase lacked activity towards crystalline cellulose and carboxymethyl cellulose.

• 산업기술연구
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• 제29권A호
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• pp.161-167
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• 2009

The bifunctional Xylanase-Cellulase hybrid protein was constructed by gene fusion. Two genes corresponding to endoxylanase gene (xylS) and endocellulase gene (celA) were amplified by PCR from Bacillus licleniformis NBL420. It was then linked through splicing by overlap extension (SOE) by PCR method. The two resulting fused hybrids, xyl/cel and cel/xyl, which differ by its orientation, were confirmed by its nucleotide sequencings. One of two fusion genes, xyl/cel was successfully expressed into pET22b(+) vector (pxyl/cel) with bifunctional xylanase-cellulase activity. On the contrary, the other cel/xyl fusion protein showed only cellulase activity with much decreased xylanase activity. Enzymatic properties of Xyl/Cel fusion protein were investigated regarding optimum pH, optimum temp, thermostability, and pH stability. It was revealed that Xyl/Cel fusion protein retained the bifunctional xylanase-cellulase activities eventhough two enzymes were connected with each other directly. These informations could be useful for construction of other hybrid proteins as well as increased range of substrate utilization.

• Asian-Australasian Journal of Animal Sciences
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• 제26권7호
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• pp.945-951
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• 2013

In vitro studies were undertaken to develop an appropriate fibrolytic enzymes cocktail comprising of cellulase, xylanase and ${\beta}$-D-glucanase for maize stover with an aim to increase its nutrient utilization in sheep. Cellulase and xylanase added individually to ground maize stover at an increasing dose rates (0, 100, 200, 400, 800, 1,600, 3,200, 6,400, 12,800, 25,600, 32,000, 38,400, and 44,800 IU/g DM), increased (p<0.01) the in vitro dry matter digestibility and in vitro sugar release. The doses selected for studying the combination effect of enzymes were 6,400 to 32,000 IU/g of cellulase and 12,800 to 44,800 IU/g of xylanase. At cellulase concentration of 6,400 IU/g, IVDMD % was higher (p<0.01) at higher xylanase doses (25,600 to 44,800 IU/g). While at cellulase doses (12,800 to 32,000 IU/g), IVDMD % was higher at lower xylanase doses (12,800 and 25,600 IU/g) compared to higher xylanase doses (32,000 to 44,800 IU/g). At cellulase concentration of the 6,400 to 32,000 IU/g, the amount of sugar released increased (p<0.01) with increasing levels of xylanase concentrations except for the concentration of 44,800 IU/g. No effect of ${\beta}$-D-glucanase (100 to 300 IU/g) was observed at lower cellulase-xylanase dose (cellulase-xylanase 12,800 to 12,800 IU/g). Based on the IVDMD, the enzyme combination cellulase-xylanase 12,800 to 12,800 IU/g was selected to study its effect on feed intake and rumen fermentation pattern, conducted on 12 rams (6 to 8 months; $20.34{\pm}2.369$ kg body weight) fed 50% maize stover based TMR. The total volatile fatty acids (p<0.01) and ammonia-N concentration was higher in enzyme supplemented group, while no effect was observed on dry matter intake, ruminal pH and total nitrogen concentration.

• 미생물학회지
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• 제47권3호
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• pp.225-230
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• 2011

유일 탄소원으로 palm kernel meal (PKM)과 밀기울을 함유한 최소배지에서 농후배양하여 작물 재배 토양으로부터 xylan과 locust bean gum (LBG)에 대한 분해활성이 있는 균을 분리하였다. 분리균 YB-1106의 16S rRNA 유전자 염기서열을 조사한 결과 Microbacterium arabinogalactanolyticum와 98% 유사도를 보였다. 분리균의 xylanase는 밀기울, oat spelt xylan, 미강 및 xylose와 같은 부가탄소원에 의해 생산성이 증가된 반면에 mannanase는 LBG와 PKM에 의해 생산성이 증가되었다. 특히 Xylanase는 밀기울 2%를 첨가한 배지, mannanase는 1% LBG를 첨가한 배지에서 각각 생산성이 가장 높았으며 모두 정지기에서 생산이 되었다. 분리균의 배양 상등액은 $50^{\circ}C$와 pH 6.0에서 mannanase의 최대활성을 보였으며, $50^{\circ}C$와 pH 6.5에서 xylanase의 최적반응 활성을 나타냈다. Mannanase에 의해 분해된 LBG와 xylanase에 의해 분해된 xylan으로부터 각각 분해산물로 올리고당이 관찰되었다.

• 한국미생물·생명공학회지
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• 제11권1호
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• pp.23-32
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• 1983

본 연구에서는 Aspergillus niger KG79에서 두종류의 D-xylanase를 분리.정제하여 그 특성을 규명하였다. 이 두 종류의 D-xylanase의 물리화학적 및 동력학적 특성은 큰 차이가 없었다. 이들 Xylanase는 D-Xylan으로부터 Xylose, Xylobiose와 Xylotriose를 분해 생성하였다. 그러나 보리짚 Xylan을 기질로 사용했을 경우에는 Xylanase I 은 II보다 측쇄 arabinose를 상당히 빨리 분해하였다. 이들 효소에 의한 Xylan의 분해도는 기질의 종류에 따라 차이가 나서 보리짚 Xylan과 larchwood Xylan의 분해도는 각각 10%와 25%(환원당량) 정도로 나타났다. 순수정제된 Xylanase와 $\beta$-Xylosidase를 사용하여 재조합한 Xylanase계의 기질분해력을 비교한 결과 최적조건에서 보리짚과 larchwood Xylan은 각각 28%와 54%씩 분해 전환되었다. 이러한 결과는 Xylan의 효소분해도의 제한요소는 기질의 물리적 특성의 차이에 기인함을 추정할 수 있었다.

• 한국미생물·생명공학회지
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• 제20권5호
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• pp.543-550
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• 1992

Hemicellulose를 효소에 의하여 분해기키기 위하여 Aspergillus niger NRC 107로부터 xylanase와 $\beta$-xylosidase의 생산조건에 대하여 조사하였다. 이들 효소 생산 최적 pH는 6.0이었으며 탄소원 중 corn-cob xylan과 질소원 중 $NaNO_{3}$이 효소 생산에 제일 좋은 기질이었으며 이들의 최적농도는 각각 15g/l와 2.67g/l이다. 이들 효소는 인산염($KH_2P0_4$)과 Tween-80의 농도를 조절하므로 수율을 높일 수 있으며 wheat bran은 xylanase의 생산에L(-) sorbose는 $\beta$-xylosidase의 생산에 좋은 영향을 주었다. 이와 같이 이 Aspergillus niger NRC 107의 회분식 배양에서 이들 효소에 영향을 미치는 생산조건을 최적화한 결과 xylanase는 39.43 units/ml, $\beta$-xylosidase는 4.2units/ml 까지 생산할 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제21권11호
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• pp.1659-1664
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• 2008

To study the working mechanisms for non-starch polysaccharidases to improve the growth performance of broiler chickens, a 21-day feeding trial was conducted. Two dietary treatments were included: 1) wheat diet (the control); 2) wheat+xylanase diet (xylanase, Allzyme PT, Alltech, Kentucky, USA). There were 8 replicates with 8 birds each for each treatment and the experimental diets were given to birds from hatch. Feed intake and body weight were measured on days 7 and 21. At the same ages, samples were taken for the determination of selected groups of luminal and mucosa-associated bacteria, mucosal morphology, brush-border membrane (BBM) bound enzyme activity and ileal nutrient digestibility. The xylanase supplement increased (p<0.05) body weight gain (BWG) and improved feed conversion ratio (FCR) at the end of the experiment but protein and starch digestibilities were not affected (p>0.05) by xylanase. Up to day 7, xylanase increased the counts of C. perfringens in the ileum and total anaerobic bacteria (TAB) in the caeca (p<0.05, p=0.07, respectively). By day 21, the counts of ileal lactobacilli (p<0.05) and TAB (p=0.07) were lower in birds given the xylanase-supplemented diet than in those on the control diet. No significant differences were observed in the counts of mucosa-associated lactobacilli and coliforms between xylanase treatment and the control at both ages. Villus height at the jejunum was not affected (p>0.05) by the supplement but crypt depth at the same site was reduced at day 7. Also, xylanase tended to increase the concentration of BBM protein (p = 0.09) and the specific activity of sucrase (p = 0.07) at day 21.