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

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

• Journal of Microbiology and Biotechnology
• /
• 제8권3호
• /
• pp.258-263
• /
• 1998

${\beta}$-Xylosidase was purified from the recombinant Escherichia coli carrying the Bacillus sp. KK-1 ${\beta}$-xylosidase gene (xylB). The molecular mass of the purified enzyme was estimated to be 62 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, the apparent molecular mass of the ${\beta}$-xylosidase was 140 kDa, indicating that the native ${\beta}$-xylosidase has an oligomeric structure composed of two identical subunits. The isoelectric point was determined to be pH 5.5. The enzyme was highly active on p-nitrophenyl-$\beta$-D-xylopyranoside but it barely hydrolyzed xylan substrates, and did not exhibit activity towards carboxymethylcellulose and p-nitrophenyl-${\beta}$-D- glucopyranoside. The enzyme had a pH optimum for its activity at pH 6.5 and a temperature optimum at $40^{\circ}C$. The enzyme activity was completely inhibited by the presence of $Hg^{++}$, and also markedly inhibited by D-xylose and D-glucose.

• Journal of Microbiology and Biotechnology
• /
• 제8권1호
• /
• pp.14-20
• /
• 1998

Syntheses of the B. stearothermophilus xylanolytic enzymes such as xylanases, ${\beta}$-xylosidases, ${\alpha}$-arabinofurano-sidases, and esterases, were observed to be regulated by the carbon source present in the culture media. Xylan induced synthesis of ${\beta}$-xylosidase at the highest level while xylose gave about 30% of the ${\beta}$-xylosidase activity induced by xylan. The lowest syntheses of the xylanolytic enzymes above mentioned were detected in the basal medium containing glucose as a sole carbon source. When a mixture of xylan and glucose was used as a carbon source, we could observe glucose repression of xylanase (about 70-fold) and ${\beta}$-xylosidase (about 40-fold) syntheses. Whereas, the level of the glucose repression of the expression of the xylA gene encoding the major ${\beta}$-xylosidase of B. stearothermophilus was assessed to be about l0-fold when the relative amounts of the xylA transcript were determined. From the sequence of the xylA gene, we could find two CRE-like sequences (CRE-l: nucleotides ＋124 to ＋136 and CRE-2:＋247 to ＋259) within the reading frame of the xylA gene, either or both of which were suspected to be involved in catabolite repression of the xylA gene.

• 한국미생물·생명공학회지
• /
• 제24권2호
• /
• pp.197-205
• /
• 1996

The $\beta$-xylosidase was purified 99- fold from the culture supernatant of Pseudo onas sp. CB-33 by ammonium sulfate precipitation, PEI precipita- tion, DEAE-Sephadex column chromatography, Sephadex G-75 gel filtration chromatography and preparative disc gel electrophoresis. Molecular weight of the enzyme was estimated to be 44,000 by SDS polyacrylamide gel electrophoresis. The enzyme has a pH optimum for activity at 7.0 and is stable over pH 6.5-9.0. The optimal temperature of the enzyme was 45$\circ$C, and its enzymatic activity was completely inactivated at 55$\circ$C for 30 min. Km value of the enzyme for p-nitrophenyl-$\beta$-D-xylopyranoside was calculated to be 4.6 mM. The effect of various reagents on the $\beta$-xylosidase activity was investigated. The enzyme activity was completely inhibited by Hg$^{2+}$, Cu$^{2+}$ and Zn$^{2+}$. The $\beta$-xylosidase was inactivated by tryptophan-specific reagent, N-bromosuccinimide and tyrosine-specific reagent, iodine. The enzyme could degrade xylo-oligosaccharides to xylose and the enzyme was competitively inhibited by xylose. The $\beta$-xylosidase and endoxylanase from Psedomonas sp. CB-33 hydrolized xylan synergically. The purified enzyme also showed $\alpha$-L-arabinofuranosidase activity.

• 한국식품과학회지
• /
• 제25권2호
• /
• pp.89-93
• /
• 1993

한국인의 분변으로부터 분리된 Bifidobacterium sp. Int-57은 다른 장내세균에 비해 ${\beta}-xylosidase$의 높은 역가를 보였으며, xylooligomer의 bifidogenic factor의 유용성을 고려하였을 때 효소생산에 초점을 둔 결과 최적 탄소원으로는 xylose였는데, 일반적으로 최종생산물은 feedback inhibition, feedback repression 등으로 효소 생산을 억제하는 일반 이론과는 상이한 결과를 보였다. 또한 xylose는 1.1%일 때 가장 높은 효소역가를 보였다. 질소원으로서는 yeast extract였고, 그 농도가 0.04%일 때, 무기염류 면에서는 $CoCl_2$였고, 농도가 0.0003%일 때 ${\beta}-xylosidase$의 최대 생산을 보였다.

• 한국미생물·생명공학회지
• /
• 제20권2호
• /
• pp.136-142
• /
• 1992

토양 분리균인 B.stearothermophilus chromosome의 유전자 은행으로부터 E.coli HB101 균주에 $\beta$-D-xylosidase 생산능력을 갖게하는 5.4Kb와 6.4Kb의 두 DNA 절편을 분리, pBR322에 크로닝하여 각각 pMG01과 pMG02의 재조합 플라스미드를 얻었다. 상기 두 B.stearothermophilus DNA 절편의 restriction map을 작성하고 이것을 기초로 하여 $\beta$-D-xylosidase 유전자인자의 위치를 확인함과 동시에 pUC18에 subcloning하여 각각 2.2kb와 1.0kb의 DNA 단편이 삽입된 $\beta$-D-xylosidase 양성의 pMG1와 pMG2를 분리하였다.

• Journal of Microbiology and Biotechnology
• /
• 제14권3호
• /
• pp.643-645
• /
• 2004

A $\beta$-xylosidase was purified from the culture of Trichoderma sp. SY. The ten-day-old culture filtrate was concentrated, followed by ion-exchange chromatography and gel filtration chromatography. As a result, $\beta$-xylosidase was finally purified about 53-fold and appeared as a single band by SDS-PAGE. The optimum pH and temperature were 5.0 and $55^{\circ}C$, respectively, and the molecular weight about 80 kDa. The purified $\beta$-xylosidase was found to be inhibited by various metal ions but not inhibited by xylose.

• 한국식품영양학회지
• /
• 제7권1호
• /
• pp.1-7
• /
• 1994

To investigate the characteristics of active sites of the D-xylanase and $\beta$-xylosidase purified from Penicillium verruculosum, effects of various chemicals on the enzyme activity were analyzed. The D-xylanase was activated by Cua), however it was inhibited by metal ions, Hg2+ and Mna+, by chemicals, N-bromosuccinimide, iodine, diethylpyrocarbonate, and 2,3-butanedione. These results suggested that the D-xylanase from Penicillium verruculosum contained tyrosine, histidine, arginine and tryptophan at the active center. The $\beta$-xylosidase was inhibited by Hg2+, N-bromosuccinimide and sodium dodecyl sulfate, however it was not effected by Mn2+ and Cu2). It was suggested that the enzyme contained tryptophan at the active center.

• Journal of Microbiology and Biotechnology
• /
• 제1권1호
• /
• pp.17-21
• /
• 1991

A gene coding for ${\beta}-xylosidase$ in alkalophilic Bacillus sp. YC-335 isolated from soil was cloned into Escherichia coli HB101 using plasmid pBR322. The recombinant plasmid pYK40 was isolated, and the cloned HindIII fragment was 15 kilobases (kb). To reduce the size of the inserted DNA fragment of pYK40, the 15 kb HindIII fragment was subjected to a series of subclonings. A 6 kb subfragment was found to code for ${\beta}-xylosidase$ activity, and the recombinant plasmid was named pYK44. Southern hybridization analysis revealed that the cloned gene hybridized with 3.5 kb, 1.5 kb, and 1.0 kb of HindIII cleaved chromosomal DNA from Bacillus sp. YC-335. ${\beta}-xylosidase$ activity produced by recombinant E. coli was found to be 11 times higher than that produced by Bacillus sp. YC-335. Xylan was required to induce the production of ${\beta}-xylosidase$ in Bacillus sp. YC-335.