壳聚糖复合保鲜剂对荧光假单胞菌的抑菌活性

Antibacterial activity of chitosan composite preservative against Pseudomonas fluorescens

摘要:

本实验以1.5%壳聚糖、0.14% ε-聚赖氨酸、0.15% D-异抗坏血酸钠组成复合保鲜剂，以荧光假单胞菌为实验菌株，探究壳聚糖复合保鲜剂对水产品中的优势菌的抑菌性能和机理。实验方法：通过测定最小抑菌浓度（MIC）、抑菌圈、细菌生长曲线考察保鲜剂对荧光假单胞菌的抑菌活性，测定OD260 值、ATP 酶和 AKP 酶活性的变化，细胞超微结构（SEM）和SDS凝胶电泳法研究保鲜剂的抑菌机制。结果表明：壳聚糖复合保鲜剂对荧光假单胞菌的最低抑菌浓度（MIC）为2.24 mg/ml。壳聚糖复合保鲜剂有着显著的抑菌活性，壳聚糖复合保鲜剂导致菌体的细胞壁膜通透性增大、完整性被破坏，菌体内ATP和AKP酶活性被抑制，显著低于（p<0.05）对照组；SDS凝胶电泳表明壳聚糖复合保鲜剂使菌蛋白条带颜色变浅且造成部分蛋白条带消失；细菌超微结构（SEM）显示壳聚糖复合保鲜剂使菌体发生变形破裂，内容物大量流出，导致菌体死亡。结论：该研究证明了壳聚糖复合保鲜剂良好的抑菌性能，研究了保鲜剂对荧光假单胞菌的抑菌机理，为水产品可食性涂膜保鲜的研发提供理论支持。

Abstract:

In this experiment, 1.5% chitosan, 0.14% ε-polylysine and 0.15% Sodium D-isoascorbate were used to form a composite preservative, and Pseudomonas fluorescens was used as the experimental strain to investigate the inhibition performance and mechanism of chitosan composite preservative on the dominant bacteria in aquatic products. Methods:the inhibition activity of the preservatives against Pseudomonas fluorescens was investigated by measuring the minimum inhibitory concentration (MIC), inhibition circle and bacterial growth curve,and the changes of OD260 value, ATP and AKP activities, cellular ultrastructure and SDS gel electrophoresis were used to study the antibacterial mechanism of antistaling agent. The results showed that the minimum inhibitory concentration (MIC) of chitosan composite preservative on Pseudomonas fluorescens was 2.24 mg/ml. Chitosan compound antistaling agent had significant antibacterial activity, chitosan compound antistaling agent increased the permeability of cell wall membrane, destroyed the integrity of cell wall membrane, and inhibited the activities of ATP and AKP in bacteria, which were significantly lower than those in the control group(p<0.05). SDS gel electrophoresis showed that the chitosan composite preservative lightened the color of bacterial protein bands and caused the disappearance of some protein bands;Bacterial ultrastructure (SEM) showed that the chitosan composite preservative deformed and ruptured the bacterial body, and a large number of contents flowed out,resulting in the death of the bacteria. This study investigated the mechanism of chitosan composite preservative and proved the inhibition ability, which provides theoretical support for the edible coating preservation of aquatic products.