• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1084-1091
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• 2012

Xylooligosaccharides are functional foods mainly produced during the hydrolysis of xylan by physical, chemical, or enzymatic methods. In this study, production of xylobiose was investigated using oil palm empty fruit bunch fiber (OPEFB) as a source material, by chemical and enzymatic methods. Xylanase-specific xylan hydrolysis followed by xylobiose production was observed. Among different xylanases, xylanase from FXY-1 released maximum xylobiose from pretreated OPEFB fiber, and this fungal strain was identified as Aspergillus terreus and subsequently deposited under the accession Number MTCC- 8661. The imperative role of lignin on xylooligosaccharides enzymatic synthesis was exemplified with the notice of xylobiose production only with delignified material. A maximum 262 mg of xylobiose was produced from 1.0 g of pretreated OPEFB fiber using FXY-1 xylanase (6,200 U/ml) at pH 6.0 and $45^{\circ}C$. At optimized environment, the yield of xylobiose was improved to 78.67 g/100 g (based on xylan in the pretreated OPEFB fiber).

• The Korean Journal of Mycology
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• v.24 no.4 s.79
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• pp.255-264
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• 1996

The hydrolysis products formed from birchwood xylan by the action of an alkaline xylanase (CX-III) from alkalophilic Cephaloxporium sp. RYM-202 were xylobiose and xylooligosaccharides polymerized with more than 4 sugar molecules. This enzyme was not active on xylobiose but readily attacked xylotriose accumulating xylobiose as a major product. The predominant end-products from xylotetraose by CX-III were xylobiose and xylotriose. These results indicate that the enzyme is typically endo-type xylanase possessing transglycosidase activity. Chemical modification of CX-III with N-bromosuccinimide revealed that two tryptophan residues per molecule of CX-III were essential for its catalytic activity on xylan. On the other hand, iodoacetamide and diethylpyrocarbonate did not influence the activity of the enzyme, suggesting that cysteine and histidine residues are not involved in the active site of this alkaline xylanase.

• Journal of Nutrition and Health
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• v.49 no.5
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• pp.295-303
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• 2016

Purpose: The objective of this study was to compare the effects of three different levels of xylobiose containing sucrose on glycemic indices based on oral glucose tolerance test (OGTT) and blood glucose response in healthy adults. Methods: Healthy adults (six male and five female participants, n = 11) underwent 14~16 hr of fasting. Subsequently, all participants took 50 g of available carbohydrates from glucose, sucrose containing 7% xylobiose (XB 7), sucrose containing 10% xylobiose (XB 10), or sucrose containing 14% xylobiose (XB 14) every week on the same day for 8 weeks. Finger prick blood was taken before and 15, 30, 45, 60, 90, and 120 min after starting to eat. Results: We observed reduction of the glycemic response to sucrose containing xylobiose. The glycemic indices of XB 7, XB 10, and XB 14 were 57.0, 53.6, and 49.7, respectively. The GI values of XB 7 were similar to those of foods with medium GI, and the GI values of XB 10 and XB 14 were similar to those of foods with low GI. The postprandial maximum blood glucose rise (Cmax) of XB 14 was the lowest among the test foods. XB 7, XB 10, and XB 14 showed significantly lower areas under the glucose curve (AUC) for 0~30 min, 0~60 min, 0~90 min and 0~120 min compared to glucose. Conclusion: The results of this study suggest that sucrose containing xylobiose has an acute suppressive effect on GI and postprandial maximum blood glucose rise. In addition, levels of xylobiose in sugar may allow more precise assessment of carbohydrate tolerance despite lower glycemic responses in a dose-dependent manner.

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.447-453
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• 1986

The culture filtrate of thermophilic alkalophilic Bacillus K17 strain contained two types of xylanases were purified by ammonium sulfate fractionation, DEAD-Sephadex A-50 column chromatography, CM-Sephadex C-50 column chromatography and Sephadex G-100 gel filtration. The purified enzymes were found to be homogeneous by sodium dodecyl sulfate and disc polyacrylamide gel electrophoresis. Xylanase I and II were characterized with respect to molecular weight, optimal temperature and pH, thermal and pH stability, and Michaelis constant. Xylanase II was more active and stable, and showed greater substrate affinity and molecular weight than xylanase I. The activities of xylanases I and II were inhibited by Cu$^{++}$, Ag$^+$, Hg$^{++}$ and Fe$^{++}$. Xylanase I hydrolyzed xylan to yield xylobiose and higher amount of xylooligosaccharides, but xylanase II produced xylose other than xylobiose and xylooligosacchrides.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.4
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• pp.423-427
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• 1992

During the cultivation of Penicillium verruculosum in the medium containing xylan as a sole carbon source for 26 days, xylanolytic activity and some changes were investigated. Protein content and xylanolytic activity, p-Nitrophenyl-$\beta$-D-xylopyranoside (PNPX), p-Nitrophenyl-$\beta$ -D-glucopyranoside (PNPG) hydrolytic activities were increased until 8 days but reducing sugar content was not correlated to protein content. When crude proteins from the culture broth were separated on SDS-PAGE, distribution of proteins was different from the culture broth of cellobiose octaacetate (COA) medium. The culture broth of xylan medium had high hydrolytic activity on xylan but not on cellulose. Furthermore, xylanolytic products were showed xylose, xylobiose and oligosaccharides on thin layer chromatography, and xylobiose was major product. Those result suggested that xylanolytic activity of culture broth was endo-type hydrolysis. Optimum temperatures of xylanolytic activity and PNPX hydrolytic activity of culture broth were 50~6$0^{\circ}C$ and 60~7$0^{\circ}C$, respectively and optimum pHs were 3.0~4.0 and 4.0~5.0, respectively.

• Journal of Nutrition and Health
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• v.50 no.1
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• pp.41-52
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• 2017

Purpose: The objective of the study was to investigate the effects of xylobiose-sugar mixture intake on defecation frequency and constipation symptoms in 31 young women with constipation. Methods: Thirty-one subjects were assigned to two groups, and subjects in each group were administered 10 g of a 7% xylobiose-sugar mixture (Experiment 1: XBS, n = 15) or 10 g of a 7% xylobiose-sugar mixture containing coffee mix (Experiment 2: XBS coffee mix, n = 16) twice per day for 6 weeks. During the study, clinical efficacy was assessed by a daily diary record. The subjects recorded their defecation frequency and fecal characteristics. Results: During pretreatment week, mean defecation frequency of XBS subjects was 2.13 times/week, whereas that of XBS coffee mix subjects was 1.56 times/week. The mean defecation frequencies of XBS and XBS coffee mix subjects increased significantly to 3.73 times/week (p < 0.05) and 3.56 times/week by week 6 (p < 0.05), respectively. After treatment with either XBS or XBS coffee mix, patients presented significant improvements in their amounts of stool, feelings of residual stool leftness, and abdominal pain symptoms (p < 0.05). The total constipation scoring system (CSS) for diagnosing constipation symptoms significantly decreased in the XBS group (10.53 score vs 7.22 score) and in the XBS coffee mix group (10.75 score vs 6.51 score) after 6 weeks. Improvement due to intake of 7% xylobiose-containing sugar seemed to last during the experimental period. Conclusion: The addition of approximately 7% xylobiose to commercially available sweeteners has been shown to improve constipation.

• Microbiology and Biotechnology Letters
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• v.11 no.3
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• pp.187-192
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• 1983

Three kinds of xylanases, X-C, X-I, and X-II, were separated from culture filtrate of an alkalophilic bacteria, Bocillus licheniformis OR-1. Their molecular weights were estimated to be 29, 000, 50, 000, and 34, 000, respectively. They were most active at pH 6.0-6.5, and at temperature of 5$0^{\circ}C$. Mercurc ion and p-chloromercurybenzoate inhibited the xylanase activity of X-C and X-II remarkably, whereas X-I was not affected. Xylanase X-I hydrolyzed barley straw xylan liberating xylose, xylobiose, and arabinose, while X-C and X-II produced only xylobiose and xylotriose.

• 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.

• 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.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1014-1021
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• 2004

Two thermostable xylanases, designated XynA and XynB, were purified to homogeneity from the culture supernatant of Paenibacillus sp. DG-22 by ion-exchange and gel-filtration chromatography. The molecular masses of xylanases A and B were 20 and 30 kDa, respectively, as determined by SDS-PAGE, and their isoelectric points were 9.1 and 8.9, respectively. Both enzymes had similar pH and temperature optima (pH 5.0-6.5 and $70^{\circ}C$), but their stability at various temperatures differed. Xylanase B was comparatively more stable than xylanase A at higher temperatures. Xylanases A and B differed in their $K_m$ and $V_{max}$ values. XynA had a $K_m$ of 2.0 mg/ml and a $V_{max}$ of 2,553 U/mg, whereas XynB had a K_m$ of 1.2 mg/ml and a $V_{max}$, of 754 U/mg. Both enzymes were endo-acting, as revealed by their hydrolysis product profiles on birchwood xylan, but showed different modes of action. Xylotriose was the major product of XynA activity, whereas XynB produced mainly xylobiose. These enzymes utilized small oligosaccharides such as xylotriose and xylotetraose as substrates, but did not hydrolyzed xylobiose. The amino terminal sequences of XynA and XynB were determined. Xylanase A showed high similarity with low molecular mass xylanases of family 11.