Laccase catalysed grafting of phenolic onto xylan to improve its applicability in films

2015 Global Conference on Polymer and Composite Materials

材料科学;化学

Pei, Jicheng^1 ; Wang, Bing^1 ; Zhang, Fangdong^1 ; Li, Zhongyang^1 ; Yin, Yunbei^1 ; Zhang, Dongxu^1

Tianjin Key Laboratory of Pulp and Paper, Tianjin University of Science and Technology, Tianjin

300457, China^1

关键词: Anti-bacterial activity;    Antibacterial effects;    Benzene ring structure;    Catalysed oxidation;    Corynebacterium glutamicum;    Fourier transform infrared spectrums;    Stretching vibrations;    Value added applications;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/87/1/012041/pdf
DOI  :  10.1088/1757-899X/87/1/012041

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Xylan can be tailored for various value-added applications. However, its use in aqueous systems is hampered by its complex structure, and small molecular weight. This research aimed at improving the xylan molecular weight and changing its structure. Laccase-catalysed oxidation of 4-coumaric acid (PCA), ferulic acid (FA), syringaldehyde (SD), and vanillin (VA) onto xylan was grafted to study the changes in its structure, tensile properties, and antibacterial activities. A Fourier transform infrared (FTIR) spectrum analyser was used to observe the changes in functional groups of xylan. The results showed a band at 1635 cm-1corresponding to the stretching vibration of conjugated carbonyl carboxy hemoglobin and a benzene ring structure were strengthened; the appearance of a new band between 1200 cm-1and 1270 cm-1corresponding to alkyl ethers on the aryl C-O stretching vibration was due to the fact that during the grafting process, the number of benzene ring structures increased and covalent connections occurred between phenols and xylan. The reaction mechanism for the laccase-catalysed oxidation of phenol compounds onto xylan was preliminary explored by13C-NMR. The results showed that PCA-xylan, FA-xylan graft poly onto xylan by Cγester bond, SD-xylan graft poly onto xylan by ether bond and an ester bond, and VD-xylan graft poly onto xylan by ether bond. The film strength of xylan derivatives has been significantly increased, especially for the PCA-xylan derivative. The increases in tensile stress at break, tensile strength, tensile yield stress, and Young's modulus were: 24.04%, 31.30%, 55.56%, and 28.21%, respectively. After laccase/phenolics were modified, xylan had a good antibacterial effect to E. coli, Corynebacterium glutamicum, and Bacillus subtilis. The SD-xylan, FA-xylan, and PCA-xylan showed a greater efficacy against E. coli, Corynebacterium glutamicum, and Bacillus subtilis, respectively.