Two-step enzymatic functionalisation of polyamide with phenolics

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• 作者：Enrique Herrero Acero^a ; Doris Ribitsch^a ; ^{doris.ribitsch@acib.at} ; Rosario Diaz Rodriguez^b ; Anita Dellacher^c ; Sabine Zitzenbacher^a ; Annemarie Marold^a ; Katrin J. Greimel^a ; Marc Schroeder^b ; Andreas Kandelbauer^d ; ^e ; Sonja Heumann^b ; Gibson S. Nyanhongo^b ; Helmut Schwab^a ; ^c ; Georg M. Guebitz^a ; ^b
• 关键词：Polyamide ; Polyamidase ; Laccase ; Enzymatic grafting
• 刊名：Journal of Molecular Catalysis B ; Enzymatic
• 出版年：2012
• 期刊代码：55_13811177
• 类别：ce
• 出版时间：July, 2012
• 卷：79
• 期：Complete
• 页码：54-60
• 文件大小：454 K

摘要

A two step enzymatic process for grafting phenolics onto polyamides (PAs) was developed in order to impart special functionalities to inert PA. Therefore, a polyamidase (NfpolyA) from Nocardia farcinica was overexpressed in Escherichia coli BL21-Gold(DE3) and purified in a single step. With p-nitroacetanilide as a substrate, NfpolyA revealed a specific activity of 20 U mg^鈭? compared to 1.5 U mg^鈭? for the wild-type enzyme. NfpolyA showed a K_M value of 0.12 卤 0.01 mM and a k_cat of 19.1 s^鈭? which were both higher than measured for the wild-type enzyme (k_cat = 3.5 s^鈭?; K_M = 0.06 mM). A laccase from Trametes hirsuta was used to oxidize ferulic acid, used as a phenol model substrate and study the covalent grafting of n-butylamine, as model substrate for PA. According to LC-MS, up to three equivalents of n-butylamine were bound to ferulic acid after laccase oxidation of ferulic acid. Both enzymes were used sequentially in a two step process. In a first step the polyamidase is used to partially hydrolyze the amide bond, leading to a surface with amine and carboxylic acids. In a second step, by using a laccase from T. hirsuta ferulic acid was grafted onto the surface of PA as confirmed with FTIR-ATR analysis.