Enzyme immobilization on ultrafine cellulose fibers via poly(acrylic acid) electrolyte grafts
Enzyme immobilization on ultrafine cellulose fibers via poly(acrylic acid) electrolyte grafts
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DOI：
10.1002/bit.20324
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发表时间：
2005-05-20
影响因子：
3.8
通讯作者：
Hsieh, YL
中科院分区：
文献类型：
--
作者：
Chen, H;Hsieh, YL
将超细纤维素纤维（直径200-400 nm）表面接枝聚丙烯酸（PAA），通过铈离子引发聚合或甲基丙烯酸甲酰化（MACI）和丙烯酸自由基聚合的方式。随着反应时间（2 ~ 24 h）、单体浓度（0.3 ~ 2.4 M）和引发剂浓度（1 ~ 10 mM）的增加，铈离子引发的PAA接枝率增加，范围在5.5 ~ 850%之间。随着MACI与纤维素羟基的摩尔比（MACI/OH, 2-6.4）和单体丙烯酸（AA）与引发剂过硫酸钾（KPS）的摩尔比（[AA]/[KPS], 1.5-6）的增加，甲基丙烯酸纤维素纤维上PAA接枝量也有所增加，范围在12.8% ~ 29.4%之间。两种情况下，随着PAA接枝量的增加，脂肪酶的吸附量（1 mg/ml脂肪酶和pH 7）和吸附脂肪酶的活性（pH 8.5, 30℃）均下降。当接枝量为5.5% PAA时，甲基丙烯酸酯纤维和接枝纤维的吸附活性分别为1.28 g/g PAA和4.3 U/mg脂肪酶；当接枝量为12.8% PAA时，甲基丙烯酸酯纤维和接枝纤维的吸附活性分别为0.33 g/g PAA和7.1 U/mg脂肪酶。接枝纤维的性质、吸附行为和脂肪酶的活性表明，通过铈引发反应得到的接枝纤维呈凝胶状，通过甲基丙烯酸基化和聚合得到的接枝纤维呈刷状。在铈离子引发的接枝表面上吸附的脂肪酶比粗酶具有更强的有机溶剂稳定性。在第二和第三个实验周期中，吸附的脂肪酶分别表现出0.5和0.3的初始活性。(c) 2004 Wiley期刊公司
Ultrafine cellulose fiber (diameter 200-400 nm) surfaces were grafted with polyacrylic acid (PAA) via either ceric ion initiated polymerization or methacrylation of cellulose with methacrylate chloride (MACI) and subsequent free-radical polymerization of acrylic acid. PAA grafts by ceric ion initiated polymerization increased with increasing reaction time (2-24 h), monomer (0.3-2.4 M), and initiator (1 - 10 mM) concentrations, and spanned a broad range from 5.5-850%. PAA grafts on the methacrylated cellulose fibers also increased with increasing molar ratios of MACI to cellulosic hydroxyl groups (MACI/OH, 2-6.4) and monomer acrylic acid (AA) to initiator potassium persulfate (KPS) ratios ([AA]/[KPS], 1.5-6), and were in a much narrower range between 12.8% and 29.4%. The adsorption of lipase (at 1 mg/ml lipase and pH 7) and the activity of adsorbed lipase (pH 8.5, 30 degrees C), in both cases decreased with increasing PAA grafts. The highest adsorption and activity of the lipase on the ceric ion initiated grafted fibers were 1.28 g/g PAA and 4.3 U/mg lipase, respectively, at the lowest grafting level of 5.5% PAA, whereas they were 0.33 g/g PAA and 7.1 U/mg lipase, respectively, at 12.8% PAA grafts on the methacrylated and grafted fibers. The properties of the grafted fibers and the absorption behavior and activity of lipase suggest that the PAA grafts are gel-like by ceric-initiated reaction and brush-like by methacrylation and polymerization. The adsorbed lipase on the ceric ion-initiated grafted surface possessed greatly improved organic solvent stability over the crude lipase. The adsorbed lipases exhibited 0.5 and 0.3 of the initial activity in the second and third assay cycles, respectively. (c) 2004 Wiley Periodicals, Inc.