Ratanapongleka Karnika, Punbut Supot
a Department of Chemical Engineering, Faculty of Engineering , Ubon Ratchathani University , Ubon Ratchathani , Thailand.
Environ Technol. 2018 Feb;39(3):336-345. doi: 10.1080/09593330.2017.1301563. Epub 2017 Mar 21.
This research has focused on the optimization of immobilized laccase condition and utilization in degradation of acetaminophen contaminated in aqueous solution. Laccase from Lentinus polychrous was immobilized in barium alginate. The effects of laccase immobilization such as sodium alginate concentration, barium chloride concentration and gelation time were studied. The optimal conditions for immobilization were sodium alginate 5% (w/v), barium chloride 5% (w/v) and gelation time of 60 min. Immobilized laccase was then used for acetaminophen removal. Acetaminophen was removed quickly in the first 50 min. The degradation rate and percentage of removal increased when the enzyme concentration increased. Immobilized laccase at 0.57 U/g-alginate showed the maximum removal at 94% in 240 min. The removal efficiency decreased with increasing initial acetaminophen concentration. The K value for immobilized laccase (98.86 µM) was lower than that of free laccase (203.56 µM), indicating that substrate affinity was probably enhanced by immobilization. The immobilized enzyme exhibited high activity and good acetaminophen removal at pH 7 and temperature of 35°C. The activation energies of free and immobilized laccase for degradation of acetaminophen were 8.08 and 17.70 kJ/mol, respectively. It was also found that laccase stability to pH and temperature increased after immobilization. Furthermore, immobilized laccase could be reused for five cycles. The capability of removal and enzyme activity were retained above 70%.
本研究聚焦于固定化漆酶条件的优化及其在水溶液中对乙酰氨基酚的降解应用。从多孔香菇中提取的漆酶被固定在海藻酸钡中。研究了海藻酸钠浓度、氯化钡浓度和凝胶化时间等漆酶固定化的影响因素。固定化的最佳条件为海藻酸钠5%（w/v）、氯化钡5%（w/v）和凝胶化时间60分钟。然后将固定化漆酶用于去除乙酰氨基酚。乙酰氨基酚在前50分钟内迅速被去除。随着酶浓度的增加，降解率和去除百分比也随之增加。固定化漆酶浓度为0.57 U/g-海藻酸盐时，在240分钟内显示出最大去除率为94%。去除效率随着初始乙酰氨基酚浓度的增加而降低。固定化漆酶的K值（98.86 μM）低于游离漆酶的K值（203.56 μM），表明固定化可能增强了底物亲和力。固定化酶在pH 7和温度35°C时表现出高活性和良好的乙酰氨基酚去除效果。游离漆酶和固定化漆酶降解乙酰氨基酚的活化能分别为8.08和17.70 kJ/mol。还发现固定化后漆酶对pH和温度的稳定性有所提高。此外，固定化漆酶可重复使用五个循环。去除能力和酶活性保持在70%以上。
