具有抗菌效应的聚羟基脂肪酸酯生物塑料的制备与功能表征

Preparation and characterization of polyhydroxyalkanoate bioplastics with antibacterial activity

摘要:

聚羟基脂肪酸酯 (polyhydroxyalkanoates, PHAs) 作为一类新型的生物高分子材料，因其多样的材料性质与高度的生物可降解性日益受到关注。使用乳酸链球菌素 (Nisin)，一种被公认为安全的天然食品防腐剂，制备了具有高效、持久抗菌效应的PHA塑料。首先采用溶剂浇铸的方法将Nisin整合到正3-羟基丁酸-3羟基己酸共聚酯 (PHBHHx)，一种具备高度生物相容性的PHA中，从而获得了具有抗菌效应的PHBHHx薄膜。激光共聚焦显微镜观察表明Nisin在PHBHHx中呈颗粒状均匀分布。随后以条件致病菌藤黄微球菌Micrococcus luteus为测试菌株，通过琼脂扩散法，测定PHBHHx薄膜抗菌效应对Nisin含量的依赖关系；在液体培养条件下测量PHBHHx薄膜的Nisin释放效果与抗菌效应。结果表明Nisin可从PHBHHx薄膜顺利释放且Nisin的含量高于25 μg/g时即表现出显著的抑菌效果且可长时间维持。该研究为工业化生产具有抗菌效应的PHA奠定了重要的技术基础，拓展了PHA在医学和食品领域的应用潜力。

Abstract:

Polyhydroxyalkanoates (PHAs), as a novel class of biopolymer, are attracting more attention due to their diverse material properties and environment-independent biodegradability. Here we report the preparation of PHA exhibiting efficient antibacterial activity by embedding Nisin, a food additive generally recognized as safe, into poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx), a type of PHA with high biocompatibility. We first prepared Nisin-containing PHBHHx films using solvent casting method. Confocal laser scanning microscopy analysis showed that a well-mixed integrated structure of the films with an even distribution of the Nisin particles in the PHBHHx matrices. Then the antimicrobial activity of PHBHHx/Nisin films against Micrococcus luteus was quantified on agar plate by measuring the size of inhibition zone. Cultivation in liquid media further confirmed the releasing of Nisin from the films and the long-time antibacterial activity. Results showed that the threshold of Nisin concentration for long-time and effective inhibition against bacteria growth is 25 μg/g. These results altogether establish a technological foundation for the application of PHA in biomedicine and food industry.