Application of carboxymethyl cellulose-g-poly(acrylic acid-co-acrylamide) hydrogel sponges for improvement of efficiency, reusability and thermal stability of a recombinant xylanase

Shohreh Ariaeenejad, Elnaz Hosseini, Elaheh Motamedi*, Ali A. Moosavi-Movahedi, Ghasem Hosseini Salekdeh

*Corresponding author for this work

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Enzyme immobilization onto supports could improve its specificity, storage stability, reusability, pH tolerance and thermal stability. Aiming to provide a proficient immobilization carrier for a recombinant xylanase (PersiXyn1), the high-performance 3D copolymeric network of carboxymethyl cellulose (CMC)-based hydrogel sponges were synthesized using in situ graft radical polymerization. While typical purified gel drying in a vacuum oven made CMC/Acrylate-Hydrogel, the freeze-drying of the resultant swelled Hydrogel containing different amounts of water, resulted in two samples of sponges (i.e., CMC/Acrylate-Sponge1 and CMC/Acrylate-Sponge2). The structural characteristics and water absorbency properties of all the as-prepared samples were evaluated. CMC/Acrylate-Sponge2 was selected for PersiXyn1 immobilization due to its homogeneous porous polymeric skeleton and maximum water absorbency (166.6 g/g) offering superb enzyme immobilization efficiency (100%). Moreover, presence of numerous oxygenated functionalities and cage-like characteristics in the CMC/Acrylate-Sponge2, led to effective electrostatic attractions between support and enzyme providing physically stabilized and reusable bio-conjugates which exhibited up to 60% recovered activity even after eight continuous reuse cycles. The results of kinetic studies indicated that the specific activities of free and immobilized PersiXyn1 were 4157 and 5508 µmol min−1 mg−1, respectively. Interestingly, CMC/Acrylate-Sponge2 support could noticeably broaden the temperature endurance ranges of immobilized PersiXyn1. While free enzyme could preserve only 10% of its maximum activity, the immobilized enzyme maintained 35% of its maximum activity after 60 min incubation at 60 °C. Lastly, CMC/Acrylate-Sponge2 support provided remarkable enzyme protection from denaturing, which caused shifting enzyme unfolding temperature from 71.5 to 78.0 °C, indicating the effectual shielding effects of polymeric support on PersiXyn1.

Original languageEnglish
Article number122022
Pages (from-to)1-11
Number of pages11
JournalChemical Engineering Journal
Volume375
DOIs
Publication statusPublished - 1 Nov 2019

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Keywords

  • PersiXyn1
  • Enzyme immobilization
  • Thermal stability
  • Hydrogel spong
  • Graft polymerization

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