Study On The Construction And Performance Of Multi-substrate Enzyme Catalysis System

Enzymatic Biofuel cell（EBFC）is a kind of fuel cell that can convert the chemical energy released in the oxidation process of biomass fuel（sugar,alcohol and organic acid）into electrical energy through bioelectrochemical pathway catalyzed by biological enzymes.It has the characteristics of high efficiency,high specificity,etc.,and has attracted wide attention due to its advantages of sustainable regeneration,good biocompatibility,mild operating conditions,etc.Since biofuels such as lactate and glucose are ubiquitous in nature and in human body fluids,EBFCs powered by these substances have the potential to power wearable and implantable electronic devices.Although EBFC has a very attractive application prospect,the current research on the performance of EBFC is still in the immature stage.The performance of EBFC is limited by the slow electron transfer rate between enzyme and electrode,which leads to problems such as low output power and short service life of EBFC.The main reason for these problems is that the active center of oxidase is embedded in the inner shell of the protein,resulting in a large distance between the active center of the enzyme and the electrode,and the electron cannot be transferred to the electrode surface quickly.Therefore,based on the above two main problems,this paper proposes a method to improve the performance of EBFC.The specific research contents are as follows:（1）Carbon nanotube interlaced carbon nanoribbon composites（CNTs/CNRs）were synthesized by one-step method.After hydrothermal nitrogen doping and further annealing at 1600℃,defects rich three-dimensional composites（N-CNTs/CNRs-1600）were formed.N-CNTs/CNRs-1600 complex three-dimensional porous structure,which not only can promote the electron transfer rate,but also can increase the activity of enzyme load and provide more site,therefore,N-CNTs/CNRs-1600 compounds as the carrier of enzyme electrode material is suitable,and through the fixator with strong oxidizing reducing four sulfur rich tile material（the vera.TTF）modification on the enzyme electrode,the preparation of biological enzyme biological cathode,anode and enzymes to build single enzyme lactate/O₂ biological fuel cell and double enzyme lactate/glucose/O₂ biological fuel cells.（2）Based on a novel complex N-CNTs/CNRs-1600 as carrier material,a lactate/O₂biofuel cell with enzyme and mediator double-immobilization was constructed to prepare lactate oxidase（LOx）/TTF bioanode and bilirubin oxidase（BOD）/2,2’-diazo-bis-3-ethylbenzothiazoline-6-sulfonic acid（ABTS）biocathode was prepared.The effects of the concentration of TTF and the amount of LOx modification on the electrochemical performance of ABTS biocathode were investigated.The results of cyclic voltammetry showed that when the concentration of TTF was 30 m M and the amount of LOx was 4μL,the catalytic current reached the maximum.The open circuit potential and power density were 0.62 V,70.7μW cm^-2 and 0.58 V,18.6μW cm^-2 in PBS and human tears,respectively.（3）In order to further improve the power density of EBFC,a multi-enzyme lactate/glucose/O₂biofuel cell based on a novel N-CNTs/CNRs-1600 composite was constructed to prepare LOx/Glucose dehydrogenase（GDH）/1,4-naphthoquinone（1,4-NQ）bioanode and bilirubin oxidase（BOD）biocathode.The results showed that 1,4-NQ had a strong catalytic ability for LOx and GDH,and the enzyme electrode was electrochemically tested by cyclic voltammetry,which realized the utilization of multiple substrates in tears.