Mimetic Enzyme Activity And Application Of Magnetic Nanoparticles Extracted From Stenotrophomonas Sp

Because of the controllable size,elaborate and complex structure,excellent performance,this new functional nanoparticles of biosynthesis have become an important research direction in the field of materials,biology and chemistry.In this study,a strain producing magnetic nanoparticles was screened from the Xiuyuan Lake of Heilongjiang university of science and technology.The strain was identified as Stenotrophomonas genus after a series of physiological and biochemical characteristics and comparative analysis of 16S rDNA sequence,named LNOl.This strain can produce a circle magnetic nanoparticles about the size of 50-80nm around the cell which were purified by ultrasonic crushing.The nanoparticles were analyzed the components of a mixture of iron phosphate and iron oxide by X-ray diffraction and spectroscopy.A sheet-like morphology was observed in high resolution transmission electron microscope.It was found that the magnetic nanoparticles with peroxidase mimetic activity could oxidize horseradish peroxidase substrate TMB to soluble blue product.In this paper,the enzyme properties of magnetic nanoparticles and horseradish peroxidase were determined and compared,results showed that the magnetic nanoparticles’tolerance to temperature was higher,up to 60℃,and the reaction rate is faster.Mimetic enzyme activity of magnetic nanoparticles can be applied to aspects of decolorization and electrochemical biosensors.In the study of decolorization,nanoparticles had some bleaching effect to the four different structure types of dyes(crystal violet,methyl orange,mordant red,methylene blue) and the decolorization rate could reach 60% after 4h reaction.After the decolorization conditions of methylene blue were optimized,the decolorization rate reached 92.6%.This study provides basis for the application of inorganic nanomaterials for dye decolorization.In addition to the application of the dye bleaching,the paper also studied the application of magnetic nanoparticles as electrode material in electrochemical biosensors.Detecting trace amounts of hydrogen peroxide by electrochemical method had not only high sensitivity,easy to operate, but also less affected by external environment and good reproducibility,which is very meaningful for practical application and detection.