Co‐immobilization of cellulase and glucose oxidase on graphene oxide by covalent bonds: a biocatalytic system for one‐pot conversion of gluconic acid from carboxymethyl cellulose

Abstract

BACKGROUND The objective of this research was to use a step‐by‐step method to prepare a novel biocatalytic system (GO‐CEL‐E/N‐GA‐GOD): ‐OH and ‐COOH on the surface of graphene oxide (GO) were used to immobilize cellulase (CEL) and glucose oxidase (GOD), respectively, which may be easier to control the loading of enzymes with different kinds, to achieve the one‐pot conversion of gluconic acid from carboxymethyl cellulose (CMC). RESULTS The loadings capability of CEL and GOD on GO‐CEL‐E/N‐GA‐GOD were 49.07 ± 7.47 mg g−1 and 10.22 ± 2.03 mg g−1, respectively. The multi‐enzyme systems had shallow temperature and pH optima of 40 °C and 5.0. The kinetic constants of GO‐CEL‐E/N‐GA‐GOD (of CEL‐GOD) were Km = 0.15 ± 0.02 (0.43 ± 0.09) mmol L−1, Vmax = 0.18 ± 0.01 (0.21 ± 0.07) μmol L−1 s−1, and kcat/Km = 24.12 ± 0.52 (17.74 ± 0.85) s−1 mmol−1 L. Nearly 65% of the initial activity of GO‐CEL‐E/N‐GA‐GOD could be retained after seven cycles. Notably the conversion of gluconic acid was able to reach 63.82 ± 8.03% within 2 h. CONCLUSION Step‐by‐step immobilization method made full use of different functional groups on GO, avoiding the competition for fixed sites between CEL and GOD in the immobilization processes. The results reflected the feasibility of the strategy to build bio‐microsystem as CEL and GOD immobilized on GO by covalent bonds to achieve the conversion from CMC to gluconic acid in one‐step. © 2019 Society of Chemical Industry

Immobilization of Multi-Enzymes on Support Materials for Efficient Biocatalysis

“…Randomly immobilized enzymes resulted into extremely efficient substrate channeling with a transient time of close to 0 s, owing to direct molecular channeling of the close to one another enzymes. Inspired from the previous works, a multi-enzyme system for one-pot production of gluconic acid from carboxymethyl cellulose was achieved by co-immobilization of cellulase and GOx on graphene oxide via covalent bonding (Zhang et al, 2020 ). Moreover (reduced), graphene oxide hybrids can also be used to fabricate multi-enzyme systems for sensitive biosensing (Dey and Raj, 2014 ; Li et al, 2018 ).…”

Cellulose-deconstruction potential of nano-biocatalytic systems: A strategic drive from designing to sustainable applications of immobilized cellulases

“…The results indicated it as a potential candidate for cellulosic ethanol production. Similarly, Zhang et al [120] studied the co-immobilization of glucose oxidase and cellulase using graphene oxide as support-material. The one-pot modification of gluconic acid from CMC due to feasible control of loading enzymes with different sorts was reported.…”

Recombinant Fungal Cellulases for the Saccharification of Sugarcane Bagasse

“…Cellulase enzymes play an important role in industrial processes, representing about 20% of the global enzyme market worldwide and presenting a wide range of application, from food, feed, textile, pulp and pulp industries. An application that has been growing in recent years is the conversion of biomass into fermentable sugars for the production of biofuels [4][5][6].…”