Surface Modulation of Graphene Oxide for Amidase Immobilization with High Loadings for Efficient Biocatalysis.

Kongliang Xu,Bin Wang,Chenlu Si,Yuguo Zheng,Renchao Zheng,Chaoping Lin

doi:10.3390/biom11101399

Kongliang Xu, Bin Wang + Show 4 more

Open Access

https://doi.org/10.3390/biom11101399

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Journal: Biomolecules	Publication Date: Sep 23, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: Zhejiang University of Technology

Abstract

As a type of important and versatile biocatalyst, amidase immobilization on solid materials has received broad attention with its relatively easy procedure and available reusability. However, current porous supports have suffered from limited loadings, and it is highly desired to develop a new type of material with abundant space so as to ensure a high loading of amidase. Here, graphene oxide was adopted as the support for amidase immobilization, which showed the highest loading capacity for amidase (~3000 mg/g) to date. To the best of our knowledge, it is the first case of amidase immobilized on graphene oxide. Through surface modulation via reducing the contents of oxygen-containing functional groups, activity recovery of immobilized amidase increased from 67.8% to 85.3%. Moreover, surface-modulated graphene oxide can efficiently uptake amidase under a wide range of pH, and the maximum loading can reach ~3500 mg/g. The resultant biocomposites exhibit efficient biocatalytic performance for asymmetric synthesis of a chiral amino acid (i.e., L-4-fluorophenylglycine, an intermediate of aprepitant).

Highlights

Amidases or amide hydrolases (EC 3.5.1.X) are a type of important versatile biocatalyst, which have been employed in the production of various chiral amino acids, carboxylic acids and amides via the cleavage of C-N bonds [1]
The immobilized amidase on graphene oxide (GO)-3 maintained its 93.0% activity after five times of usage (Figure 4b), while amidase@GO only maintained 63% activity under the same condition, which can be attributed to the increased hydrophobic interaction force via surface modulation, as discussed above
It has been demonstrated that graphene oxide can serve as an efficient support for amidase immobilization, which shows the highest loading capacity (~3000 mg/g) to date

Summary

Introduction

Amidases or amide hydrolases (EC 3.5.1.X) are a type of important versatile biocatalyst, which have been employed in the production of various chiral amino acids, carboxylic acids and amides via the cleavage of C-N bonds [1]. With the increasing demand of green chemistry, amidases have received broad attention in pharmaceutical and chemical industries for the production of D- or L-amino acids and β-lactam antibiotics due to their high activity and specificity under mild conditions [1,2]. The intrinsically fragile nature of enzymes under incompatible conditions (e.g., high temperature, unfavorable pH and organic solvents) greatly limits the industrialization of amidases [3]. To improve their stability and recyclability, various methods have been developed, such as enzyme immobilization, protein engineering and so on [4]. In search of an ideal support for amidase immobilization, various materials with different compositions, structures and morphologies have been explored [5], including inorganic carries (e.g., mesoporous silica) [6], organic carries (e.g., chitosan and nanocrystalline cellulose) [7,8], composite carriers (e.g., silica nanoflower and metal–organic framework hybrids) [9], etc

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