• Korean Journal of Microbiology
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• v.46 no.3
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• pp.308-312
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• 2010

Deinococcus geothermalis is a moderate thermophillic radiation resistant bacterium producing greater abundance of sugar metabolism enzymes than other Deinococcus species. In this study, optimal condition for xylanolytic activity of D. geothermalis was determined and xylooligosaccharides from oat spelt, beechwood, and birchwood xylan hydrolysates by this organism were analyzed through HPLC. Reducing sugar yield was increased in the order of beechwood, birchwood, and oat spelt xylan. D. geothermalis displayed maximal xylanolytic activity at $40^{\circ}C$ and pH 8.0. Magnesium ion increased xylanolytic activity upto 7.5 fold. Six kinds of xylooligosaccharides (xylose, xylobios, xylotriose, xylotetraose, xylopentaose, and xylohexalose) were detected from beechwood and birchwood xylan reaction products. Among them, xylose was the major product. However, only three kinds of xylooligosaccharides (xylose, xylopentaose, and xylohexalose) were clearly detected from oat spelt xylan. Gamma-ray (50 kGy) treatment of beechwood xylan, birchwood xylan and oat spelt xylan increased xylanolytic activity of D. geothermalis. The results indicate that D. geothermalis and pretreatment of radiation is useful for xylooligosaccharides production.

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.383-388
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• 2009

A strain YB914 was isolated from soil as a producer of the extracellular xylanase, which catalyzes the hydrolysis of oat spelt xylan. The strain YB914 was identified as Streptomyces sp. on the basis of its morphological, cultural and biochemical properties. The xylanase of culture filtrate was the most active at $55^{\circ}C$ and pH 5.5, and retained 80% of its maximum activity at the range of pH 4.5~7.0. In order to optimize the culture medium for xylanase production, ingredients of G.S.S medium were replaced by several carbohydrates. The carbohydrates such as oat spelt xylan, corn cob xylan, wheat bran and lactose increased the xylanase productivity of Streptomyces sp. YB914. However, xylanase production was greatly repressed by galactose or arabinose. The maximum xylanase productivity was reached to 48 U/mL in the modified medium containing 1% oat spelt xylan and 1.5% lactose.

• Journal of Life Science
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• v.17 no.4 s.84
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• pp.568-574
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• 2007

Lignin degrading bacterium Pseudomonas sp. LG2 was able to degrade lignin substrate to a lot of APPL compound. APPL compound was detected in culture supernatants from Pseudomonas sp. LG2 grown with BSC(brewer's spent grain). FAE(ferulic acid esterase) and xylanase are induced from Pseudomonas sp. LG2 in the presence of carbon sources such as oat spelt xylan, HBSG I, II(hydrolyzed brewer's spent grain I, II) and AFBSG(autoclaved fraction from brewer's spent grain). However, xylanase and FAE are not induced by growth of Pseudomonas sp. LG2 on xylose and arabinose. Pseudomonas sp. LG2 is grown on medium containing oat spelt xylan, HBSG I, II and AFBSG and the induction of FAE and xylanase activities of extracellular proteins determined during 14 days. Maximum level of xylanase activity(5.3 U/mg) found at 6 days in culture contained oat spelt xylan as carbon source, whereas maximum level of FAE activity(15.4 mU/mg) was found at 8 days in culture contained AFBSG as carbon source. Most ferulic acid was released in culture supernatants when Pseudomonas sp. LG2 grown on oat spelt xylan, HBSG I, II and AFBSG. FAE of extracellular enzymes was also specific activity on methyl ferulic acid, methyl caffeic acid and methyl p-coumaric acid respectively, but not methyl sinapinic acid, methyl vanillic acid and methyl gallic acid.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.147-152
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• 2009

A xylanase was purified from the culture supernatant of Bacillus sp. A-6 by using ultrafiltration and ion exchange chromatography on the column of SP-Sepharose using 5 mM acetate buffer, pH 5.0. The xylanase was eluted from the column at the concentration less than 0.05 M NaCl. The eluted xylanase was shown to be a single protein band in SDS-PAGE. Zymogram analysis indicated that the protein band in SDS-PAGE had the enzyme activity to hydrolyze oat spelt xylan. The molecular weights of the xylanase were 15,000 based on SDS-PAGE and 14,100 based on gel filtration chromatography. Thin layer chromatography showed that the xylanase hydrolyzed oat spelt xylan into xylobiose and high-molecular-weight xylooligosaccharides. The relative activities of the heated xylanase decreased to 80% at $40^{\circ}C$ after 7 hr and less than 40% at $60^{\circ}C$ after 1 hr.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.307-313
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• 2008

The yeast surface expression system, pCTXYN (6.8 kb), of Bacillus endoxylanase gene (xynB, 642 bp) was constructed and introduced into Saccharomyces cerevisiae EBY100 cell. The transformed yeast cell showing the highest endoxylanase activity was selected through the active staining of colonies grown on YPDG medium containing xylan. With the yeast transformant, EBY100/pCTXYN, grown on galactose containing medium, it was found that the endoxylanase was successfully displayed on the yeast cell surface and the xylooligosaccharides were efficiently produced from xylan. The most of endoxylanase activity was detected in the cell fraction and reached about 1.9 unit/mL after 48 h cultivation. The optimized conditions for xylooligosaccharides production from xylan were determined as follows: substrate and its concentration, oat spelt xylan 6%; concentration of yeast whole-cell, 5 unit/mL; temperature, $50^{\circ}C$, and reaction time $2{\sim}4\;h$. When the oat spelts xylan and corncob xylan were hydrolyzed by treatment with cell surface-displayed endoxylanase, xylotriose was formed as a main product.

• Journal of Microbiology and Biotechnology
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• v.6 no.3
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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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• v.16 no.12
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• pp.1856-1861
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• 2006

A Bacillus sp. A-6 strain that produced xylanase was isolated from rice bran. The optimal temperature and pH for xylanase activity of the culture supernatant of Bacillus sp. A-6 were 40$^{\circ}C$ and pH 7, respectively. The optimal temperature and pH for xylanase production in the xylan medium were 30$^{\circ}C$ and pH 9, respectively. The optimal concentrations of oat spelt xylan and peptone for xylanase production were 0.5% and 1.5%, respectively. The best nitrogen sources for xylanase production was beef extract, but xylanase production was also supported comparably by tryptone and peptone. The bacterial growth in the optimal xylan medium reached stationary growth phase after 12 h of incubation. The xylanase production in the culture supernatant increased dramatically during the initial 12 h exponential growth phase and then remained constant at 23.8-24.5 unit/ml during the stationary growth phase. The pH of the culture medium decreased from 8.8 to 6.7 during the exponential growth phase and subsequently increased to 8.1 during the stationary growth phase. Rice bran, sorghum bran, and wheat bran as well as oat spelt xylan induced xylanase production. The xylanase production was repressed when glucose was added to the xylan-containing medium.

• Microbiology and Biotechnology Letters
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• v.48 no.2
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• pp.158-166
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• 2020

A gene coding for the xylanase was cloned from Paenibacillus woosongensis, followed by determination of its complete nucleotide sequence. This xylanase gene, designated as xyn10A, consists of 1,446 nucleotides encoding a polypeptide of 481 amino acid residues. Based on the deduced amino acid sequence, Xyn10A was identified to be a modular enzyme composed of a catalytic domain highly homologous to the glycosyl hydrolase family 10 xylanase and a putative carbohydrate-binding module (CBM) in the C-terminus. By using DEAE-sepharose and phenyl-sepharose column chromatography, Xyn10A was purified from the cellfree extract of recombinant Escherichia coli carrying a P. woosongensis xyn10A gene. The N-terminal amino acid sequence of the purified Xyn10A was identified to exactly match the sequence immediately following the signal peptide predicted by the Signal5.0 server. The purified Xyn10A was a truncated protein of 33 kDa, suggesting the deletion of CBM in the C-terminus by intracellular hydrolysis. The purified enzyme had an optimum pH and temperature of 6.0 and 55-60℃, respectively, with the kinetic parameters V_max and K_m of 298.8 U/mg and 2.47 mg/ml, respectively, for oat spelt xylan. The enzyme was more active on arabinoxylan than on oat spelt xylan and birchood xylan with low activity for p-nitrophenyl-β-xylopyranoside. Xylanase activity was significantly inhibited by 5 mM Cu²⁺, Mn²⁺, and SDS, and was noticeably enhanced by K⁺, Ni²⁺, and Ca²⁺. The enzyme could hydrolyze xylooligosaccharides larger than xylobiose. The predominant products resulting from xylooligosaccharide hydrolysis were xylobiose and xylose.

• Journal of Microbiology and Biotechnology
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• v.6 no.3
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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.

• Korean Journal of Microbiology
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• v.31 no.2
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• pp.157-165
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• 1993

A 1, 4-.betha.-D-xylanase, designated as xylanase II, was purified from the culture filtrate of Trichoderma koningii ATCC 251131 by column chromatography on Sephadex G-75, SP-Sephadex C-50, DEAE-Sephadex A-50 and Sephadex G-50 with an overall yield of 6.97%. It has a molecular weight of 21.000 and an isoelectric point of 9.4. The enzyme activity is optimal at pH 5.0 and at a temperature of 50.deg.C. Xylanase II is stable up to 50.deg.C, while 40 and 90% of its activity are lost after the incubation for 30 and 60 min at 60.deg.C. The enzyme degrades xylan with relatively high activity, as well as carboxymethylcellulose and Avicel. Its $K_{m}$ values for oat-spelt xylan, larchwood xylan and Avicel are 7.48, 1.98 and 13.33 mg/ml, respectively. The hydrolysis products of oat-spelt xylan by xylanase II are xylose, xylobiose, xylotriose and arabinoxylotriose, while the reaction products of larchwood xylan are xylose, xylobiose, xylotriose and small amount of higher oligomers. The action paterns of the enzyme demonstrate that xylanase II is endo-enzyme.