一种新型纤维素基吸附剂的制备及其对漆酶的固定化性能研究

Preparation of a Novel Cellulose-based Adsorbent and Its Immobilization Performance Towards Laccase

利用NaOH/尿素体系溶解纤维素并加入纳米碳酸钙,而后在盐酸溶液中再生,制得具备多孔结构的纤维素小球;之后采用丙烯酰胺对纤维素小球的羟基进行改性,接枝碳链并引入酰胺基,在碱性条件下酰胺基水解为羧基,得到改性纤维素基吸附剂;其可通过静电吸附和氢键间作用力固定漆酶。对接枝改性和漆酶固定化的最佳条件进行了探索,得到最佳改性条件为:时间6 h、温度50℃、单体配比8∶5、引发剂浓度0.08%;最佳固定化条件为:pH值=5.0、初始酶浓度10 g/L、固定化时间3 h。利用此最佳改性纤维素小球在最佳条件下固定的漆酶具有良好的热稳定性和可重复使用性,酶活提高了52%。结果表明,改性纤维素小球作为一种新型的绿色载体,在漆酶固定化方面具有广阔的应用前景。

A novel modified cellulose-based adsorbent was prepared in this study:cellulose was dissolved in NaOH/urea solution with addition of nano-CaCO3,which was then regenerated in HCl solution to prepare cellulose microsphere with porous structure. The as-prepared cellulose microsphere was further modified with acrylamide,leading to graft of carbon chain and introduction of acylamino which would be hydrolyzed to carboxyl under alkaline condition. The modified cellulose adsorbent immobilized laccase through electrostatic adsorption and hydrogen bond. The optimal conditions were duration of 6 h,temperature 50℃,monomer ratio 8∶5 for graft modification and pH value of 5. 0,initial laccase concentration 10 g/L,time 3 h for immobilization of laccase. Under such conditions,laccase immobilized on the modified cellulose microspheres showed a significantly improved enzymatic activity by 52%. Moreover,good performances on thermal stability and reusability of immobilized laccase were obtained. The results indicate that the modified cellulose microsphere,as green-based carrier,possesses promising application prospects in laccase immobilization.