Immobilization of cellulase on magnetoresponsive graphene nano-supports

Ankush A. Gokhale, Jue Lu, Ilsoon Lee

Research output: Contribution to journalArticle

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Abstract

In this study, we report the preparation of pH tunable, temperature sensitive magnetoresponsive graphene-based nano-bio carriers for cellulase immobilization. We discuss a simple route to overcome the geometric disadvantage imposed by most 2D immobilization supports and make them capable of closely mimicking free enzymes (FE) operating under similar reaction conditions. The supramolecular assembly of oppositely charged quenched polyelectrolytes and maghemite-magnetite nanoparticles on 2D graphene supports followed by covalent immobilization of cellulase shows a marked improvement in the bio-receptivity of graphene supports. The incorporation of magnetic nanoparticles opens up the possibility of recovery and reuse of the enzyme over multiple cycles. The immobilized enzymes retained about 55% of the original specific activity even after four cycles of reuse. Cellulase immobilization is achieved by a combination of annealed polyelectrolyte brushes and zero-length spacer molecules. The swelling behavior of annealed polyelectrolyte brushes is a strong function of the environmental conditions. The degree of polyelectrolyte swelling can be easily tweaked by manipulating the pH and temperature, providing us an effective tool to control the activity of immobilized enzymes. At a pH of 5.1 and a temperature of 50 °C, the immobilized enzymes with the annealed polyelectrolyte brushes displayed close to 1.5-fold improvement in the activity as compared to immobilized enzymes without the brushes. Activity of immobilized cellulase is evaluated using both soluble as well as insoluble substrates like 2% (w/v) CMC and avicel respectively.

LanguageEnglish (US)
Pages76-86
Number of pages11
JournalJournal of Molecular Catalysis B: Enzymatic
Volume90
DOIs
StatePublished - Jun 2013

Profile

Graphite
Cellulase
Polyelectrolytes
Immobilized Enzymes
Immobilization
Graphene
Brushes
Enzymes
Temperature
Swelling
Magnetite Nanoparticles
Magnetite nanoparticles
Cellulose
Nanoparticles
Recovery
Molecules
Substrates

Keywords

  • Cellulase
  • Graphene
  • Layer-by-layer
  • Nanobiocatalysis
  • Polyacid brushes

ASJC Scopus subject areas

  • Biochemistry
  • Bioengineering
  • Catalysis
  • Process Chemistry and Technology

Cite this

Immobilization of cellulase on magnetoresponsive graphene nano-supports. / Gokhale, Ankush A.; Lu, Jue; Lee, Ilsoon.

In: Journal of Molecular Catalysis B: Enzymatic, Vol. 90, 06.2013, p. 76-86.

Research output: Contribution to journalArticle

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