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Preparation of mesoporous materials immobilized lignin peroxidase Characteristics

Author: XuLongQian
Tutor: WenXiangHua
School: Tsinghua University
Course: Environmental Science and Engineering
Keywords: Mesoporous materials Lignin peroxidase Immobilization Stability
CLC: TB383.4
Type: Master's thesis
Year: 2010
Downloads: 129
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Abstract


Lignin peroxidase (LiP) for refractory pollutants degradation with efficient, but weak stability and difficult to reuse shortcomings limit its practical application. Immobilization is to solve these problems is one of the most effective methods, but not many studies carried out in this study with excellent performance around the synthesis and design of immobilized enzyme carrier screening suitable immobilization strategies, conducted a series of studies . P123 triblock copolymer used as template to 1,3,5 - triisopropylbenzene (TIPB) as swelling agent, in NaAC-HAC buffer mesoporous materials. Systematically investigated the silicon source, swelling agent dosage, initial synthesis pH, initial synthesis temperature on the properties of mesoporous materials. The results showed that when tetraethyl ester (TMOS), tetraethyl orthosilicate (TEOS) and liquid sodium silicate (NaSi) as a silicon source, could be obtained for \like \Increasing the dosage of swelling agent, the sample aperture increases, but decreased pore order degree, but also by the rule of macroscopic morphology becomes irregular cylindrical block. Gradually increasing the initial synthesis pH, the sample morphology achieved by the lumps into spherical particles shift to the worm-like pore structure consists of two-dimensional hexagonal shape and vesicle-like changes. Improve initial synthesis temperature, the samples from the macroscopic morphology of neat little ball gradually to larger particle size spherical particles and the shell was converted, and the temperature is low and easy to obtain two-dimensional hexagonal mesoporous. Determine the optimum conditions for the synthesis of mesoporous materials: selection of TMOS as silica source, TIPB dosage of 1.0g, initial synthesis pH and temperature were 3.5 and 12 ℃. Choose the optimum conditions for the synthesis of mesoporous materials immobilized LiP physical adsorption was investigated, and the dosage of enzyme immobilization time on the immobilization effect. Determine the initial amount of enzyme and carrier optimum ratio of 76.8mg / g, optimum immobilization time was 12 h. Protein loading time 8.87mg / g, apparent activity of immobilized LiP 41.45U/mg. LiP immobilized pH stability and thermal stability has been greatly improved, and has good storage stability. 6 times repeated use, immobilization can be retained only 30% of LiP activity. After the grafting method using, use γ-aminopropyl triethoxysilane (APTES), and β-aminoethyl-γ-aminopropyl trimethoxysilane (AEAPMDS) are two functions modifier mesoporous materials - NH2 modification. Vector modified by chemical adsorption method for the immobilization of LiP. The protein load was 4.63mg / g and 4.49mg / g, apparent activity immobilized respectively 10.22U/mg LiP and 10.55U/mg. Optional glutaraldehyde, terephthalic isothiocyanate, triazine and four kinds of a carbodiimide coupling agent covalently coupled LiP immobilized found triazine best immobilization method, protein loading of 12.15mg / g, LiP activity was apparent 541.9U/mg, compared with the free LiP, which has a stronger acid resistance, but less sensitive to temperature; repeated use and has excellent performance. 0.25mM of Acid Orange on immobilized LiP in 200s within its decolorization rate 30%; repeated bleaching five times, managed to maintain 60% of the decolorization rate.

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