Bioinspired Immobilization of Glycerol Dehydrogenase by Metal Ion-Chelated Polyethyleneimines as Artificial Polypeptides

Engineering in Life Sciences

Ren

et al. 2018

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Featuring unique planar structure, large surface area and biocompatibility, graphene oxide (GO) has been widely taken as an ideal scaffold for the immobilization of various enzymes. In this regard, nickel‐coordinated graphene oxide composites (GO‐Ni) were prepared as novel supporters for the immobilization of formate dehydrogenase. The catalytic activity, stability and morphology were studied. Compared with GO, the enzyme loading capacity of GO‐Ni was enhanced by 5.2‐fold, besides the immobilized enzyme GO‐Ni‐FDH exhibited better thermostability, storage stability and reuse stability than GO‐FDH. GO‐Ni‐FDH retained 40.9% of its initial activity after 3 h at 60°C, and retained 31.4% of its initial relative activity after 20 days’ storage at 4°C. After eight times usages, GO‐Ni‐FDH maintained 63.8% of its initial activity. Mechanism insights of the multiple interactions of enzyme with the GO‐Ni were studied, considering coordination bonds, hydrogen bonds, electrostatic forces, coordination bonds, and etc. A practical and simple immobilization strategy by metal ions coordination for multimeric dehydrogenase was developed.

Section: Resultsmentioning

confidence: 99%

Assembly of graphene oxide‐formate dehydrogenase composites by nickel‐coordination with enhanced stability and reusability

Lin

Engineering in Life Sciences

Ren

et al. 2018

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“…The further increase of LPEI concentration was shown to be unfavourable for the bi‐enzymatic reaction. Interestingly, LPEI <400 µmol L –1 proved to have little influence on the parental GDH and NOX (see Fig. S6).…”

Section: Resultsmentioning

confidence: 99%

“…Because LPEI has a large amount of secondary amine groups, the resistance ability of LPEI–Mn 2+ –bHGN against pH variations was improved due to the excellent buffering capacity of LPEI which has a large amount of secondary amine groups. A similar report in which LPEI immobilization extended pH adaptability also was observed when GDH was immobilized using LPEI–metal scaffolds …”

Section: Resultsmentioning

confidence: 99%

“…In our previous work, the multi‐level interactions between LPEI, manganese ions and protein were utilized for the immobilization of GDH, a multimeric oxidoreductase. The immobilization formed LPEI–metal–enzyme nanoparticles scattering along LPEI scaffolds and significantly improving the catalytic activity and stability of immobilized GDH . Comparing with our previous report on GDH immobilization by LPEI–metal scaffolds, the presented work used bifunctional enzyme with internal covalent linkage and both N and C terminal polyhistidine‐tags to increase binding affinity between enzyme and LPEI–metal scaffolds.…”

Section: Introductionmentioning

confidence: 99%

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Preparation and evaluation of a polymer–metal–enzyme hybrid nanowire for the immobilization of multiple oxidoreductases

Chen

J of Chemical Tech & Biotech

et al. 2018

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BACKGROUND: The immobilization of multiple oxidoreductases has attracted a lot of research interest for its industrial application in eco-friendly production. Here, a novel immobilization strategy was developed using manganese ion chelated linear polyethyleneimine as artificial hybrid scaffold that allowed self-assembly of bifunctional oxidoreductase (glycerol dehydrogenase-NADH oxidase) via multipoint coordination interaction.RESULT: The immobilization formed a highly ordered polymer-metal-enzyme complex structure shaped like a leaf vein with 200-nm-wide nanowires. Preliminary results showed that the immobilization could not only retain but substantially increased the biological activity of the immobilized enzyme by 8.2-fold. The equilibrium concentration of the reaction product DHA also was increased by 4.5-fold compared with that of the free enzyme, exhibiting higher elimination efficiency of product inhibition compared with other enzyme immobilization strategy using nanoparticles or activated agarose beads. At the same time, linear polyethyleneimine (LPEI)-manganese scaffolds could prevent enzyme subunit disassociation and stabilize the active multimeric form, which improved catalytic condition adaption and thermal stability of target enzyme. CONCLUSION: These results indicated a great potential of polymer-metal-enzyme hybrid in the enzyme immobilization and have provided a simple and efficient strategy for the immobilization of multiple oxidoreductases.

“…Recently, metal-ion-chelated PEI was used for immobilization of a multimeric oxidoreductase (glycerol dehydrogenase). The CLEAs formed were stabilized by hydrogen bonding, electrostatic forces, and coordination bonding [24]. Although a cross-linker was not used to immobilize the enzyme in this study, nanoparticles of diameter 250-650 nm were obtained.…”

Section: Ionic Polymermentioning

confidence: 92%

Techniques for Preparation of Cross-Linked Enzyme Aggregates and Their Applications in Bioconversions

2018

Enzymes are biocatalysts. They are useful in environmentally friendly production processes and have high potential for industrial applications. However, because of problems with operational stability, cost, and catalytic efficiency, many enzymatic processes have limited applications. The use of cross-linked enzyme aggregates (CLEAs) has been introduced as an effective carrier-free immobilization method. This immobilization method is attractive because it is simple and robust, and unpurified enzymes can be used. Coimmobilization of different enzymes can be achieved. CLEAs generally show high catalytic activities, good storage and operational stabilities, and good reusability. In this review, we summarize techniques for the preparation of CLEAs for use as biocatalysts. Some important applications of these techniques in chemical synthesis and environmental applications are also included. CLEAs provide feasible and efficient techniques for improving the properties of immobilized enzymes for use in industrial applications.