Department of Organic Chemistry, Biochemistry and Catalysis, University of Bucharest, Soseaua Panduri 90, sector 5, 050663 Bucharest, Romania.
Institute of Organic Chemistry C. D. Nenitescu of Romanian Academy, 202B Spl. Independentei, 060023 Bucharest, Romania.
Molecules. 2020 Oct 24;25(21):4921. doi: 10.3390/molecules25214921.
This paper presents an enzyme biocatalytic method for grafting lignin (grafting bioprocess) with aniline, leading to an amino-derivatized polymeric product with modified properties (e.g., conductivity, acidity/basicity, thermostability and amino-functionalization). Peroxidase enzyme was used as a biocatalyst and HO was used as an oxidation reagent, while the oxidative insertion of aniline into the lignin structure followed a radical mechanism specific for the peroxidase enzyme. The grafting bioprocess was tested in different configurations by varying the source of peroxidase, enzyme concentration and type of lignin. Its performance was evaluated in terms of aniline conversion calculated based on UV-vis analysis. The insertion of amine groups was checked by H-NMR technique, where NH protons were detected in the range of 5.01-4.99 ppm. The FTIR spectra, collected before and after the grafting bioprocess, gave evidence for the lignin modification. Finally, the abundance of grafted amine groups was correlated with the decrease of the free -OH groups (from 0.030 to 0.009 -OH groups/L for initial and grafted lignin, respectively). Additionally, the grafted lignin was characterized using conductivity measurements, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), temperature-programmed desorption (TPD-NH/CO) and scanning electron microscopy (SEM) analyses. The investigated properties of the developed lignopolymer demonstrated its disposability for specific industrial applications of derivatized lignin.
本文提出了一种酶生物催化方法，用于将木质素（接枝生物过程）与苯胺接枝，得到具有改性性质的氨基衍生聚合物产物（例如，导电性、酸度/碱度、热稳定性和氨基官能化）。过氧化物酶用作生物催化剂，HO 用作氧化试剂，而苯胺氧化插入木质素结构遵循特定于过氧化物酶的自由基机制。通过改变过氧化物酶的来源、酶浓度和木质素类型，在不同的配置中测试了接枝生物过程。根据 UV-vis 分析计算的苯胺转化率评估其性能。通过 H-NMR 技术检查了胺基团的插入，其中在 5.01-4.99 ppm 范围内检测到 NH 质子。接枝生物过程前后收集的 FTIR 光谱证明了木质素的修饰。最后，接枝的胺基团的丰度与游离-OH 基团的减少相关（初始木质素和接枝木质素分别为 0.030 和 0.009 -OH 基团/L）。此外，使用电导率测量、凝胶渗透色谱 (GPC)、热重分析 (TGA)、程序升温脱附 (TPD-NH/CO) 和扫描电子显微镜 (SEM) 分析对接枝木质素进行了表征。所研究的开发的木质聚合物的性质表明，它可用于衍生化木质素的特定工业应用。
