Catalytic properties of the immobilized Aspergillus tamarii xylanase

Gouda, Mona K.; Abdel–Naby, Mohamed A.

doi:10.1078/0944-5013-00165

Cited by 56 publications

(28 citation statements)

References 15 publications

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“…This could be due to lower diffusion of high molecular mass substrate into immobilized beads. A similar effect was also noticed when high molecular weight substrates were used including xylan (Gouda and Abdel-Naby 2002;Dalal et al 2007). It is also reported earlier that both kinetic parameters were increased after immobilization of xylanase when adsorption technique was employed.…”

Section: Resultssupporting

confidence: 80%

Calcium alginate matrix increases the stability and recycling capability of immobilized endo-β-1,4-xylanase from Geobacillus stearothermophilus KIBGE-IB29

2015

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Exploration of microbial pool from extremely diversified ecosystem is significantly important for various industrial applications. Bacterial communities from extreme habitats including volcanic vents, hot springs, and industrial sectors are eagerly explored for the isolation of thermophiles. Geobacillus stearothermophilus KIBGE-IB29, isolated from blast furnace site of a steel processing industry, is capable of producing thermostable endo-β-1,4-xylanase. In the current study, this enzyme was immobilized within calcium alginate beads using entrapment technique. Amalgamation of sodium alginate (40.0 gL(-1)) and calcium chloride (0.4 M) was used for the formation of immobilized beads. It was observed that temperature (50 °C) and pH (7.0) optima of immobilized enzyme remained same, but enzyme-substrate reaction time increased from 5.0 to 30.0 min as compared to free enzyme. Diffusion limit of high molecular weight xylan (corncob) caused a decline in V max of immobilized enzyme from 4773 to 203.7 U min(-1), whereas K m value increased from 0.5074 to 0.5722 mg ml(-1) with reference to free enzyme. Immobilized endo-β-1,4-xylanase showed its stability even at high temperatures as compared to free enzyme and retained 18 and 9 % residual activity at 70 and 80 °C, respectively. Immobilized enzyme also exhibited sufficient recycling efficiency up to five reaction cycles which indicated that this enzyme can be a plausible candidate in paper and pulp industry.

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Section: Resultssupporting

confidence: 80%

Calcium alginate matrix increases the stability and recycling capability of immobilized endo-β-1,4-xylanase from Geobacillus stearothermophilus KIBGE-IB29

2015

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“…An Arrhenius plot of logarithm of inactivation constant (k i ) against the reciprocal of the absolute temperature showed higher values of activation energy for the immobilized xylanase (227 kcal/mol) as compared to free xylanase (210 kcal/mol) confirming lesser temperature sensitivity for the immobilized xylanase. A similar increase in thermostability has been reported by Gouda & Abdel-Naby (2002).…”

Section: Effect Of Temperature On Stability Of Immobilized and Free Xsupporting

confidence: 77%

Immobilization of Xylan-Degrading Enzymes from Scytalidium thermophilum on Eudragit L-100

Gaur

Khare

2005

World J Microbiol Biotechnol

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Xylanase from Scytalidium thermophilum was immobilized on Eudragit L-100, a pH sensitive copolymer of methacrylic acid and methyl methacrylate. The enzyme was non-covalently immobilized and the system expressed 70% xylanase activity. The immobilized preparation had broader optimum temperature of activity between 55 and 65°C as compared to 65°C in case of free enzyme and broader optimum pH between 6.0 and 7.0 as compared to 6.5 in case of free enzyme. Immobilization increased the t 1/2 of enzyme at 60°C from 15 to 30 min with a stabilization factor of 2. The K m and V max values for the immobilized and free xylanase were 0.5% xylan and 0.89 lmol/ml/min and 0.35% xylan and 1.01 lmol/ml/min respectively. An Arrhenius plot showed an increased value of activation energy for immobilized xylanase (227 kcal/mol) as compared to free xylanase (210 kcal/mol) confirming the higher temperature stability of the free enzyme. Enzymatic saccharification of xylan was also improved by xylanase immobilization.

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“…Increased thermostability of xylanase after immobilization on aluminum oxide pellets was also recorded by Nagar et al (2012b). Immobilization of an enzyme often protects it against heat inactivation (Gouda and Abdel-Naby 2002). The improved temperature stability of xylanase may boost its suitability for industrial application.…”

Section: Effect Of Temperature On Immobilized Xylanasementioning

confidence: 90%

Immobilization of xylanase purified from Bacillus pumilus VLK-1 and its application in enrichment of orange and grape juices

et al. 2014

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This study was conducted to evaluate the efficacy of purified free and immobilized xylanase in enrichment of fruit juices. Extracellular xylanase produced from Bacillus pumilus VLK-1 was purified to apparent homogeneity by 15.4-fold with 88.3 % recovery in a single step using CMSephadex C-50. Purified xylanase showed a single band on SDS-polyacrylamide gel with a molecular mass of 22.0 kDa. The purified enzyme was immobilized on glutaraldehydeactivated aluminum oxide pellets and the immobilization process parameters were optimized statistically through response surface methodology. The bound enzyme displayed an increase in optimum temperature from 60 to 65ºC and pH from 8.0 to 9.0. The pH and temperature stability of the enzyme was also enhanced after immobilization. It could be reused for 10 consecutive cycles with 58 % residual enzyme activity. The potential of purified xylanase (free and immobilized) in juice enrichment from grape (Vitis amurensis) and orange (Citrus sinensis) pulps has been investigated. The optimization of this process using free xylanase revealed maximum juice yield, clarity and reducing sugar on treatment with 20 IU/g fruit pulp for 30 min at 50ºC. Treatment of both the fruit pulps with xylanase under optimized conditions resulted in an increase in juice yield, clarity, reducing sugars, titratable acidity, and filterability but a decline in turbidity and viscosity. Immobilized enzyme was more effective in improving juice quality as compared to its soluble counterpart. The results showed B. pumilus VLK-1 xylanase, in both free and immobilized form, as a potential candidate for use in fruit juice enrichment.

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Catalytic properties of the immobilized Aspergillus tamarii xylanase

Cited by 56 publications

References 15 publications

Calcium alginate matrix increases the stability and recycling capability of immobilized endo-β-1,4-xylanase from Geobacillus stearothermophilus KIBGE-IB29

Calcium alginate matrix increases the stability and recycling capability of immobilized endo-β-1,4-xylanase from Geobacillus stearothermophilus KIBGE-IB29

Immobilization of Xylan-Degrading Enzymes from Scytalidium thermophilum on Eudragit L-100

Immobilization of xylanase purified from Bacillus pumilus VLK-1 and its application in enrichment of orange and grape juices

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