介孔氧化钛与海藻酸钠固定化木聚糖酶的对比研究
Comparison of Immobilized Xylanase Using Mesoporous Titania and Sodium Alginate as Carriers
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摘要: 为了提高木聚糖酶在应用过程中的稳定性,以介孔氧化钛和海藻酸钠为载体,开展木聚糖酶固定化研究。氧化钛固定化木聚糖酶,考察了吸附时间、给酶量、温度和pH值对固定化的影响;海藻酸钠固定化木聚糖酶,考察了NaCl浓度、海藻酸钠浓度和硬化时间对固定化的影响。在此基础上,对比两种固定化木聚糖酶的稳定性。研究结果表明,优化的介孔氧化钛固定化条件为:固定化时间0.5 h,给酶量20.36 IU/g,温度65 ℃,pH值6.0,固定化木聚糖酶回收率为93.37%;优化的海藻酸钠固定化条件为:硬化时间2 h,氯化钙质量浓度为20 g/L,海藻酸钠质量浓度为35 g/L,温度65 ℃,pH值6.0,固定化木聚糖酶回收率为28.77%。相对于海藻酸钠固定化木聚糖酶和游离木聚糖酶,介孔氧化钛固定化木聚糖酶热稳定性和酸碱稳定性均优于海藻酸钠固定化木聚糖酶及游离木聚糖酶。Abstract: In order to improve the stability of xylanase in biocatalysi, mesoporous titania (M-TiO2) and sodium alginate were used to immobilize xylanase. The properties of immobilized xylanase were also investigated in this study. The optimum immobilization by mesoporous titiania was obtained as 20.36 IU/g xylanase was immobilized at 65 ℃ for 0.5 h under pH 6.0. The maximal immobilized rate is 93.37%.In contrast, the xylanase was immobilized when 35 g/L sodium alginate was selected to handle the enzyme at 65 ℃ for 2 h under pH 6.0 environment in the presence of 20 g/L CaCl2. Maximal immobilized rate is 28.77%.In regard of the free and immobilized xylanase on sodium alginate, immobilized xylanase by mesoporous titania has better thermostability and pH stability.
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