Center for Membrane and Film Technology, Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501, Japan.
Department of Materials Chemistry, Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan.
J Colloid Interface Sci. 2019 May 15;544:230-240. doi: 10.1016/j.jcis.2019.03.003. Epub 2019 Mar 2.
Enzymes play vital roles in biological transformations due to incomparable selectivity. Enzymatic membrane reactors (EMRs) combine enzymes with membranes, and many researchers have studied the synergistic effect of EMRs exerting on enzyme performance. Before the utility of EMRs can expand from natural aqueous media to organic solvents, robust membranes must be developed to promote enzyme protection from hostile forms of media. For this study, laccase was immobilized on an organic-solvent-resistant hydroxylated polyketone (PK-OH) membrane via covalent bonds and served as a model enzyme. Ketone groups facilitated the immobilization via hydrogen bonds, leading to a high immobilization density of 462 µg/cm. In homogeneous aqueous-organic solvents, the activity of immobilized laccase was up to 3.5 times greater than that of free laccase towards 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid). In addition, the results also showed improved activity towards highly concentrated 2,4,6-trichlorophenol and bisphenol A (1.4 g/L). Furthermore, the activity in filtration mode showed a 240% increase over that in batch mode. The immobilized laccase maintained its activity after 40 days of storage, 10 reuse cycles, and 50 h of continuous reaction. These results show that robust polyketone based membrane support will create opportunities for the application of EMRs in aqueous-organic solvents.
酶由于无与伦比的选择性，在生物转化中起着至关重要的作用。酶膜反应器（EMR）将酶与膜结合在一起，许多研究人员研究了 EMR 对酶性能的协同作用。在 EMR 从天然水介质扩展到有机溶剂之前，必须开发出坚固的膜来促进酶免受恶劣介质的影响。在这项研究中，漆酶通过共价键固定在耐有机溶剂的羟化聚酮（PK-OH）膜上，用作模型酶。酮基通过氢键促进固定化，导致固定化密度高达 462µg/cm。在均相水-有机溶剂中，固定化漆酶的活性比游离漆酶对 2,2'-偶氮双（3-乙基苯并噻唑啉-6-磺酸）高 3.5 倍。此外，结果还表明，对高浓度 2,4,6-三氯苯酚和双酚 A（1.4g/L）的活性也有所提高。此外，过滤模式下的活性比批处理模式下的活性提高了 240%。固定化漆酶在储存 40 天后、重复使用 10 次和连续反应 50 小时后仍保持其活性。这些结果表明，坚固的基于聚酮的膜载体将为 EMR 在水-有机溶剂中的应用创造机会。
