木质素过氧化物酶在球型介孔材料上的固定化特性研究

在醋酸-醋酸钠缓冲体系(pH=3.5)中以聚乙二醇-聚丙三醇-聚乙二醇三嵌段共聚物(P123)为模板,正硅酸甲酯(TMOS)为硅源,1,3,5-三异丙基苯(TIPB)为扩孔剂合成了具有规则六方形孔道(11.6nm)的微米级球型颗粒.以合成的介孔材料为载体,采用物理吸附法对木质素过氧化物酶(LiP)进行固定化,研究了初始酶量和固定化时间等因素对固定化效果的影响,以及固定化对LiP酶学性质和稳定性的影响.结果表明,当初始酶量(E)与载体量(MS)比为76.8mg/g,固定化反应12h时,固定化LiP可获得最大蛋白质负载量(8.87mg/g)和最大表观活性(41.45U/mg).与游离酶相比,固定化LiP的最适pH和温度均未有明显变化,但pH稳定性和热稳定性都有了不同程度的提高,在4℃条件下保存7周后固定化LiP活性几乎没有损失,且在重复使用6次后,可保留近30%的活性.

Immobilization of Lignin Peroxidase on Spherical Mesoporous Material

The spherical mesoporous particles with two-dimensional (2D) hexagonal mesopores in diameter up to 11.6 nm was fabricated in acetic acid/sodium buffer solution (pH = 3.5) by using tetramethoxysilane (TMOS) as silica source, Pluronic P123 as template and 1,3,5-triisopropylbenzene (TIPB) as swelling agent. Then the mesoporous particles were employed as carriers for the immobilization of lignin peroxidase (LiP). The effect of immobilization time, the amount of added enzyme on the immobilized enzyme amount and activities were investigated. The characteristic and stability of immobilized LiP were also studied. The results showed that, as the mass ratio of enzyme (E) and mesoporous material (MS) was 76.8 mg/g,immobilizing time was 12 h, the largest immobilized enzyme amount (8.87 mg/g) and highest apparent activity (41.45 U/mg) of immobilization LiP were achieved. Comparing with free LiP, the optimum pH and temperature of the immobilized LiP were almost the same, while whose pH stability and thermal stability were significantly improved. No obvious activity loss was observed for the immobilized LiP after 7 weeks storage at 4 degrees C. After 6 times of usage, almost 30% of the initial activity could still remain.