Crosslinked xylan as an affinity adsorbent for endo-xylanases

Rozie, H.; Somers, W.; Bonte, Anja; Rombouts, F.M.; Visser, Joost

doi:10.1016/0144-8617(92)90019-m

Cited by 7 publications

(3 citation statements)

References 15 publications

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“…Although there has been great interest in the purification of xylanases, relatively few attempts have been made by using affinity chromatography (29,34). By using the procedure described by Rozie et al (29), cross-linked xylan was prepared as an affinity adsorbent.…”

Section: Discussionmentioning

confidence: 99%

Regulation and Characterization of Xylanolytic Enzymes of Thermoanaerobacterium saccharolyticum B6A-RI

Lee

Lowe

Zeikus

1993

Appl Environ Microbiol

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During growth on xylan and xylose Thermoanaerobacterium saccharolyticum B6A-RI produced endoxylanase, 13-xylosidase, arabinofuranosidase, and acetyl esterase, and the first three activities appeared to be produced coordinately. During nonlimiting growth on xylan, these enzyme activities were predominantly cell associated; however, during growth on limiting concentrations of xylan, the majority of endoxylanase activity was extracellular rather than cell associated. Endoxylanase, 13-xylosidase, and arabinofuranosidase activities were induced by xylan, xylose, and arabinose, respectively. Acetyl esterase activity was constitutive, and endoxylanase activity was catabolite repressed by glucose. Extracellular endoxylanase existed as a highmolecular-weight complex (molecular weight, more than 106). When analyzed by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) and zymograms, the crude endoxylanase complex was composed of at least six activity bands. Endoxylanase was purified by gel filtration with Sephacryl S-300 and affinity chromatography with xylan coupled to Sepharose CL-4B preequilibrated to 45°C with 50 mM sodium acetate buffer (pH 4.0) and eluted with 0.1% soluble xylan. A single area of endoxylanase activity was identified on the zymogram; when this activity was analyzed by SDS-PAGE, it was composed of a major protein with a molecular weight of approximately 160,000 and a minor protein with a molecular weight of approximately 130,000. The endoxylanase activity stained with Schifis reagent, indicative of glycoproteins, displayed a specific activity of 41 U/mg of protein on xylan, and had pH and temperature optima of 6.0 and 70°C, respectively.

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Section: Discussionmentioning

confidence: 99%

Regulation and Characterization of Xylanolytic Enzymes of Thermoanaerobacterium saccharolyticum B6A-RI

Lee

Lowe

Zeikus

1993

Appl Environ Microbiol

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“…A slightly modified procedure demonstrated for xylan modified with epichlorohydrin was utilized herein (Rozie et al 1992). In a 250 mL round bottom flask, 2 g of xylan was added to a 1:1 water/ethanol mixture at a 1:20 ratio of carbohydrate to liquid.…”

Section: Modification Of Xylan With Succinic Anhydridementioning

confidence: 99%

Incorporation of carboxyl groups into xylan for improved absorbency

et al. 2011

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The objective of this research was to investigate green, renewable reaction systems for xylan that introduce crosslinking and carbonyl group for improved performance in water absorption applications. Xylan was modified separately with three different reaction agents, citric acid, succinic anhydride and sodium monochloracetate (SMCA). The xylan was reacted with citric acid in the presence or absence of sodium hypophosphite (SHP) as a catalyst, both in a solution form and in a semi-dry form in an oven. Acidbase titrations, FTIR, TGA, and DSC were used to confirm the composition of the reactant products. Reacted xylan had significantly increased carboxyl content, degree of esterification and degree of substitution with citric acid, succinic anhydride, and sodium monochloracetate. Effective reaction conditions were determined for high yield products. For the xylan reacted with citric acid, the catalyst (SHP) and the use of a semi-dry reaction condition increased the yield significantly. Succinic anhydride and SMCA had high yields. The reaction trends observed were consistent with similar results for starch. Increases in water absorption, saline solution absorption, and decreases in water contact angle for the xylan citrate relative to the xylan indicate that high carboxyl content materials can be generated with xylan and that the resulting materials have enhanced water affinity.

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“…The lowest affinity was found for xylan extracted from dissolving pulp followed by larchwood xylan. The last two substrates are known to possess a low degree of substitution (Gamerith and Strutzenberger, 1992; Rozie et al, 1992). Thus, the lower the degree of substitution, the lower the affinity of the enzyme for the substrate.…”

Section: Kinetic Parameters For β‐Xylanase and β‐Xylosidasementioning

confidence: 99%

Modification of the Carbohydrate Composition of Sulfite Pulp by Purified and Characterized β-Xylanase and β-Xylosidase of Aureobasidium pullulans

et al. 1999

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Both beta-xylanase and beta-xylosidase were purified to homogeneity from a xylose-grown culture of Aureobasidium pullulans. Cellular distribution studies of enzyme activities revealed that beta-xylanase was an extracellular enzyme, during both the exponential and stationary phases, whereas beta-xylosidase was mostly periplasmic associated. The beta-xylanase exhibited very high specificity for xylan extracted from Eucalyptus grandis dissolving pulp, whereas the beta-xylosidase was only active on p-nitrophenyl xyloside and xylobiose. Comparison of kcat/Km ratios showed that the beta-xylanase hydrolyzed xylan from dissolving pulp 1.3, 2.1, and 2. 3 times more efficiently than Eucalyptus hemicellulose B, Eucalyptus hemicellulose A, and larchwood xylan, respectively. The beta-xylosidase exhibited a transxylosylation reaction during the hydrolysis of xylobiose. When applied on acid sulfite pulp, both enzymes released xylose and hydrolyzed xylan to a different extent. Although beta-xylosidase (0.4 U/g pulp) liberated more xylose from pulp than beta-xylanase (4.7 U/g pulp), it was responsible for only 3% of xylan solubilization. Treatment of pulp with beta-xylanase liberated 51.7 microgram of xylose/g and hydrolyzed 10% of xylan. The two enzymes acted additively on pulp and removed 12% of pulp xylan. A synergistic effect in terms of release of xylose from pulp was observed when the enzyme mixture of beta-xylanase and beta-xylosidase was supplemented with beta-mannanase. However, this did not result in further enzymatic degradation of pulp xylan. Both beta-xylanase and beta-xylosidase altered the carbohydrate composition of sulfite pulp by increasing the relative cellulose content at the expense of reduced hemicellulose content of pulp.

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Crosslinked xylan as an affinity adsorbent for endo-xylanases

Cited by 7 publications

References 15 publications

Regulation and Characterization of Xylanolytic Enzymes of Thermoanaerobacterium saccharolyticum B6A-RI

Regulation and Characterization of Xylanolytic Enzymes of Thermoanaerobacterium saccharolyticum B6A-RI

Incorporation of carboxyl groups into xylan for improved absorbency

Modification of the Carbohydrate Composition of Sulfite Pulp by Purified and Characterized β-Xylanase and β-Xylosidase of Aureobasidium pullulans

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