Fabrication Of Microencapsulated Phase Chsnge Materials With Magnetic TiO₂ Shell And The Applied In Immobilization Of Emzyme

Candida rugosa lipase?CRL?is the common lipase that expresses specificity and high effectiveness.However,free lipase has numerous defects such as sensitiveness to high temperature and pH value of the environment,easily inactivated,difficulty reusable and so on,which limit its application.Traditionally,immobilization of CRL on various familiar supports can overcome these disadvantages and improve the lipase catalytic activity in some ways.This article reported the design and fabrication of a novel applied energy microsystem based on magnetic microencapsulated phase change materials?PCMs?as thermoregulatory enzymatic carriers for bioapplications in biotechnological and bioengineering areas.The TiO₂/Fe304 hybrid shell of the microcapsules cannot only prevent the leaking of PCMs but also improve the thermal conductivity and reduce supercoiling;crystalline TiO₂ acting as a compact and firm supporter cannot only facilitates the immobilization of enzymes but can also have characteristic of non-toxic,antimicrobial,high thermal stability,high chemical stability,good mechanical properties and et al;Fe304 inorganic nanoparticles provided the superparamagnetism for microcapsules,which were convenience the separation and reuse of the immobilization of enzymes;n-eicosane as a paraffin-type PCM was therefore selected as a core material for enzymatic carriers to perform thermal regulation and temperature.In Chapter ?,the microcapsules composed of n-eicosane core and TiO₂/Fe₃O₄ hybrid shell were designed and fabricated.Firstly,We developed a synthetic strategy to prepare the magnetic microcapsules through the self-assembly of Fe304 nanoparticles on an n-eicosane core in the Pickering emulsion templating system,followed by the interfacial polycondensation of titanic procures to form a crystalline TiO₂ domain.As a result,the microcapsules could be fabricated cleverly.Then,the as-synthesized microcapsules were functionalized with carboxyl groups,activated with succinimide groups,and then immobilized with CRL by covalent bonding through a series of reactions.We discussed the accelerating rate drops of the mixed liquor which contained of initiator impact on the as-synthesized microcapsules enzymatic carriers to select the optimum preparation conditions in the Chapter ?.When the accelerating rate drops of mixed liquor at 0.5 mL·min^-1,0.7 mL·min^-1 and 0.9 mL·min^-1,the as-synthesized microcapsules micro-morphology exhibited octahedron,commixture of similar octahedron with similar microspheres,and microspheres,respectively.And all of as-synthesized microcapsules achieved well core-shell structure.After a series of characterization,we found that the as-synthesized microcapsules synthesized at 0.9 mL·min^-1 accelerating rate drops obtained the best thermal stability and specific surface area as the enzymatic carriers.In Chapter VI,we immobilized the CRL by covalent bonds onto the as-synthesized microcapsules at the optimum preparation conditions.Then,CRL was immobilized onto these microcapsules by covalent bonds,and such covalent bonding immobilization was further testified by Fourier infrared spectrum analysis?FT-IR?and X-ray photoelectron spectroscopy?XPS?spectroscopy.The separability of the CRL-immobilized microcapsules was determined by magnetic characterization along with a visible magnetic separation experiment?VSM?.The effect of temperature on biocatalytic activity,storage stability,thermal stability and reusability of free and immobilized CRL were investigated.Compared to conventional TiO₂ carriers,the immobilized CRL on the microcapsules designed by this study exhibited a higher biocatalytic activity,longer storage stability,higher thermal stability and better reusability due to the thermoregulatory effectiveness of n-eicosane core.This study may open up a novel direction for development and applications of microencapsulated PCMs in biotechnological and bioengineering areas.