Improving the stability of cellulase by immobilization on modified polyvinyl alcohol coated chitosan beads

Dinçer, Ayşe; Telefoncu, Azmi

doi:10.1016/j.molcatb.2006.10.005

Cited by 143 publications

(63 citation statements)

References 28 publications

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“…In research using other matrices for immobilization [28] [29], enzymes did not remain stable over such a wide temperature range. Akkaya et al [30] have reported that optimal temperatures for immobilized enzyme may be higher, lower or the same as for the native enzyme.…”

Section: Discussionmentioning

confidence: 99%

Immobilization of Commercial Cellulase and Xylanase by Different Methods Using Two Polymeric Supports

Romo-Sánchez¹,

Camacho²,

Ramírez³

et al. 2014

ABB

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Industrial applications require enzymes highly stable and economically viable in terms of reusability. Enzyme immobilization is an exciting alternative to improve the stability of enzymatic processes. The immobilization of two commercial enzymes is reported here (cellulase and xylanase) using three chemical methods (adsorption, reticulation, and crosslinking-adsorption) and two polymeric supports (alginate-chitin and chitosan-chitin). The optimal pH for binding was 4.5 for cellulase and 5.0 for xylanase, and the optimal enzyme concentrations were 170 µg/mL and 127.5 µg/mL respectively, being the chitosan and the ideal support. In some cases, a low concentration of crosslinking agent (glutaraldehyde) improved stability of the immobilization process. Biotechnological characterization showed that the reusability of enzymes was the most striking finding, particularly of immobilized cellulase using glutaraldehyde, which after 19 cycles retained 64% activity. These results confirm the economic and biotechnical advantages of enzyme immobilization for a range of industrial applications.

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Section: Discussionmentioning

confidence: 99%

Immobilization of Commercial Cellulase and Xylanase by Different Methods Using Two Polymeric Supports

Romo-Sánchez¹,

Camacho²,

Ramírez³

et al. 2014

ABB

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“…This result agreed with that obtained by AbdEl-Ghaffar and Hashem (2010) for cellulase immobilized on chitosan-GDA (1%), which retained 60% of the initial activity. Dinçer and Telefoncu (2007) reported that immobilized cellulase retained 52% of its initial activity after 8 cycles of reuse. …”

Section: Repeated Hydrolysis Of Cellobiose By Immobilized Enzymementioning

confidence: 99%

Biochemical studies on immobilized fungal β-glucosidase

Ahmed

El-Shayeb

Hashem

et al. 2013

Braz. J. Chem. Eng.

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-β-Glucosidase from Aspergillus niger was immobilized on sponge by covalent binding through a spacer group (glutaraldehyde). Sponge-immobilized enzyme had the highest immobilization yield (95.67%) and retained 63.66% of the original activity exhibited by the free enzyme. The optimum pH of the immobilized enzyme remains almost the same as for the free enzyme (pH 4.0). The optimum temperature for β-glucosidase activity was increased by 10 ºC after immobilization. The activation energy (E a ) of the immobilized β-glucosidase was lower than the free enzyme (3.34 and 4.55 kcal/mol), respectively. Immobilized β-glucosidase exhibited great thermal stability and retained all the initial activity after incubation at 55 ºC for 2 h; however, the free enzyme retained 89.25% under the same condition. The calculated half-life (t ½ ) value of heat inactivation of immobilized enzyme at 60, 65 and 70 ºC was 213.62, 72.95 and 56.80 min, respectively, whereas at these temperatures the free enzyme was less stable (half-life of 200.0, 55.31 and 49.5 min, respectively). The deactivation rate constant at 65 ºC for the immobilized β-glucosidase is 9.5x10 -3 / min, which was lower than that of the free form (12.53x10 -3 / min). The immobilization process improved the pH stability of the enzyme (immobilized and free enzyme retained 69.35 and 39.86%, respectively, of their initial activity after 45 min at pH 7.5). The effect of some chemical substances on the activity of the immobilized and free β-glucosidase has been investigated. In the presence of sodium dodecyl sulfate (SDS) and p-chloromercuri benzoate (p-CMB) the immobilized enzyme retained 36.13 and 45.34%, respectively, of the initial activity, which is higher than that of free enzyme (13.71 and 1.61%, respectively). The Michaelis constant (K m ) value of the free enzyme was 40.0 mM, while the apparent K m value for the immobilized enzyme was 46.51 mM. The maximum reaction rate (v max ) of immobilized β-glucosidase was smaller than that of the free enzyme by 7.69%. Sponge-immobilized β-glucosidase was repeatedly used to hydrolyze cellobiose (5 and 8 cycles with retained activity of 67.32 and 51.04%, respectively).

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“…본 연구에서 키토산 은 비드의 형태를 만드는데 사용되었고, 셀룰라아제는 maleic anhydride로 변형시킨 PVA 막으로 코팅된 키토산 비드에 고정화되었다. 변형된 PVA를 사용함으로써 고정화된 셀룰 라아제의 3차구조를 보존하여 pH 및 온도 안정성을 향상시 키고, 최적 pH가 4.0에서 7.0으로 이동됨이 보고되었다 [11]. 따라서 본 연구에서는 변화된 효소의 최적 pH인 7.0에서 실 험을 진행하였다.…”

Section: Methodsunclassified

Properties of Cellulase Immobilized on Chitosan Beads

Lee¹,

Ha²,

Kim³

et al. 2014

KSBB Journal

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Abstract:Recently, there is a growing interest in efficient biomass pretreatment and saccharification processes to produce biofuels and biochemicals from renewable non-food biomass resources. In this study, glucose was produced from cellulose by immobilizing cellulase enzyme on chitosan beads which was reported to have high pH and temperature stability. The immobilized amounts of cellulase on chitosan beads linearly increased with increasing the concentrations of cellulase solution. The glucose production increased to 7.2 g/L from 1% carboxymethyl cellulose (CMC) substrate when immobilized at 20% cellulase solution. The maximum specific activity was 0.37 unit/mg protein when immobilized at 8% cellulase solution. At pH 7 and 37 o C, the optimum reaction composition was 0.5 g beads/L from 1% CMC substrate. At this condition, the conversion to glucose completed at ca. 20 min.

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Improving the stability of cellulase by immobilization on modified polyvinyl alcohol coated chitosan beads

Cited by 143 publications

References 28 publications

Immobilization of Commercial Cellulase and Xylanase by Different Methods Using Two Polymeric Supports

Immobilization of Commercial Cellulase and Xylanase by Different Methods Using Two Polymeric Supports

Biochemical studies on immobilized fungal β-glucosidase

Properties of Cellulase Immobilized on Chitosan Beads

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