Study On Oxidation Of 5-hydroxymethylfurfural By Galactose Oxidase/Superoxide Dismutase

As a raw material for the production of various chemicals,5-hydroxymethylfurfural(HMF)has attracted more and more attention,but with the development of industrialization,the production of pollutants in the production process has become a major problem.In this paper,a green environmental protection method was adopted to catalyze HMF,and the specific recognition of hydroxyl group by GOase was used to oxidize HMF to produce 2,5-furadiformaldehyde(DFF),and no pollutants appeared in the whole catalytic process.GOase is a copper metal enzyme that can catalyze a variety of substrates.In the process of contact with air,two electrons will be given to O2 to form H2O2,which will cause irreversible inactivation of GOase.Therefore the study at the same time the manganese superoxide dismutase(MnSOD)are introduced to reduce the influence of H2O2,MnSOD is similar to the nature of the peroxidase,it can reduce H2O2 an electron,the formation of free radicals to trigger GOase’s internal activity,or decomposition of H2O2,reducing the negative effect in the process of H2O2 on catalytic.In addition,complex fixation was also carried out around these two enzymes.By adding Cu2+ and PO43-,they were precipitated together with enzymes to form GOase/MnSOD-NF complex.The complex presents a spherical structure with extensive surface crack gaps of about 30 μm in diameter.By means of laser confocal and X-ray photoelectron spectroscopy(XPS)analysis,the enzyme proteins can be fully and uniformly distributed in the structure of the complex.In terms of catalytic HMF,the catalytic activity of free GOase and GOase-NF was compared.Under the same conditions,the conversion rate of the former was 34.78%and the latter was 51.11%.On this basis,MnSOD was introduced to form GOase/MnSOD-NF complex,and the conversion rate was increased to 77.17%.The optimal ratio of GOase to MnSOD was also explored,indicating that the catalytic activity of the compound was the highest when the concentration ratio was 0.2:0.08.At the same time,the tolerance to H2O2 after the addition of MnSOD was also tested,and it was found that the activity of GOase-NF remained only 31.9%,while the activity of GOase/MnSOD-NF remained 58.57%.