漆酶催化香草醛接枝壳聚糖及其在抗菌纸中的应用

Chitosan Grafted with Vanillin: Its Antioxidant and Antibacterial Activity and Application in Papermaking

关键词:  漆酶  壳聚糖  香草醛  抗氧化性  抑菌性

Key Words:laccase  chitosan  vanillin  antioxidant activity  antimicrobial

摘要:以香草醛（VA）为底物，利用漆酶作为催化剂催化香草醛与壳聚糖接枝反应。对VA-壳聚糖接枝产物分别进行线性电位滴定、红外光谱检测，确定产物接枝率和结构的变化，对其抗氧化性和抑菌性能进行分析并采用表面涂布法和浆内添加法制备抗菌纸。结果表明，VA-壳聚糖的接枝率约为10.2%；红外光谱分析表明氨基的吸收峰强度减弱，且在1637 cm^-1处出现新的吸收峰，说明在漆酶催化作用下香草醛与壳聚糖上的氨基参加反应形成席夫碱（CN）结构；VA-壳聚糖对ABTS·+自由基半数抑制浓度(IC50)值为1.62 mg/mL，还原能力检测得出浓度为5 mg/mL时在700 nm处的吸光度较原样提高0.321，表明VA-壳聚糖的抗氧化性能得到提高；VA-壳聚糖的抑菌性能较壳聚糖原样有所提高。采用表面涂布法和浆内添加法制备VA-壳聚糖抗菌纸，可以赋予纸张良好的抑菌性能，同时可以改善纸张的物理性能。

Abstract:Chitosans were grafted with vanillin (VA) by using laccase as catalyst. The linear potentiometric titration and Fourier-transform infrared spectroscopy (FT-IR) were used to characterize the graft ratio and structural changes in the VA-chitosan, and its antioxidant and antibacterial activity were analyzed. The results showed that the graft ratio of VA-chitosan was 10.2%. The FT-IR presented an absorption decrease of amino groups and a new band appeared at 1637 cm^-1 corresponding to the CN vibrations that was characteristic of imines due to Schiff base formed between the amino groups of chitosan and the Phenolic hydroxyl of Vanillin. The IC50 was 1.62 mg/mL for ABTS·+ scavenging of VA-chitosan, the measurement of reducing power showed that the absorbance at 700 nm was raised 0.321 compared to chitosan at the concentration of 5 mg/mL, thus the results suggested that the antioxidant activity of VA-chitosan was improved. The antibacterial activities of VA-chitosan against E. coli, S. enterica, Bacillus subtilis and Staphylococcus aureus were improved compared with the original chitosan. Antimicrobial paper was prepared using VA-chitosan by the methods of surfacing coating and addition into the pulp, the antimicrobial activity and physical properties of the prepared paper were improved.