Preparation And Application Of Magnetic Regenerative Enzyme Catalyst

As a kind of nature biological catalyst, enzyme has been paid more attention byscientists because of its excellent catalytic choice and incomparable efficiency underthe mild conditions. However, any slight variation of the reaction conditions in theenvironment around the enzyme catalyst could lead to the catalytic performancedecline, even lose activity; and enzyme catalyst recovery and recycling also havemany problems. Immobilized enzyme catalysts were still have the problems of how toseparate from the reaction system. Therefore, we need to find a high efficiency, largecapacity, easy to recycle enzyme carrier.Nanometer magnetic materials have the special magnetic effect than theconventional materials. The carrier is one of the nanometer magnetic materialsapplications. Using the magnetic field is easy to achieve the purpose of recycling formagnetic properties. The chemical properties of magnetic nanoparticles are lively,reunion and coagulation easily. So, in order to improve the dispersion and stability ofthe particles, the surface of the particles need to modificate and make it moreimportant to get a wider range of applications. Firstly, we prepared magneticferroferric oxide nanoparticles through sol-gel synthesis method and ultrasoniccoprecipitation method; compared the differences and similarities between the twomethods. The coated reagent of the silica and silane coupling agent modified offerroferric oxide nanoparticles increased its stability in the air and using environment.Through the experiment found that, directly using of silane coupling agent was betterthan two agents used. On the one hand, the coating can increase its oxidationresistance; on the other hand, it can immobilize enzyme.Using modified ferromagnetic oxide particles immobilized enzymes: α-amylasewas immobilized by KH550directly and cellulase was immobilized by glutaraldehydeactivate of coupling. Using transmission electron microscopy (TEM), X-ray powderdiffraction（XRD）, thermo-gravimetric apparatus（TGA）， infrared spectrometer（IR）, vibrating sample magnetometer (VSM) and so on characterized the preparatedof the materials, and ultraviolet-visible spectrophotometer was used to test enzyme activity of immobilized bioenzyme. The immobilized α-amylase enzyme activity canreach79.4%of free enzyme activity. Using glutaraldehyde chemical crosslinking ofimmobilized cellulase enzyme activity can be83.2%free of cellulase. Also discussedthe best conditions of preparation of immobilized α-amylase: when ferroferric oxideusage0.1g, the reaction under the condition of pH=6, water bath temperature usedin the reaction of45℃,α-amylase enzyme dosage about2%of the solution, the solidload time of3h；the best condition of preparation of immobilized cellulase werewhen ferroferric oxide usage was0.05g, water bath temperature used in the reactionof40℃, the reaction under the condition of pH=6, the amount of glutaraldehydesolution of2%, cellulose enzyme dosage was2%of the solution, the solid load timewas4h. The recycle use was also detected: the activity of the immobilized α-amylasereaduced to60.5%after4times recycling use; after immobilized cellulase used6times, enzyme activity reduced to57%.The immobilized cellulase also used todecompose the agricultural waste corn cobs. This paper discussed the pretreatment ofcorn cobs, different substrates concentration and the decomposition cycle use.We producted the regenerated enzyme composite catalysts by nanometer magneticmaterials immobilized biological enzyme. It can achieve the purpose of rapidrecycling, greatly saving the use amount of enzyme. The nanometer magneticmaterials carriers also improve the stability of the enzyme.