复合生物保鲜剂对腐败希瓦氏菌的抑菌机理

为了研究复合生物保鲜剂对冷藏带鱼优势腐败菌(腐败希瓦氏菌)的抑菌作用机理,通过牛津杯法测定了复合生物保鲜剂对腐败希瓦氏菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),并测定了复合生物保鲜剂对腐败希瓦氏菌的抑菌活力、细菌生长曲线、细胞膜完整性和细胞的稳定性,对细菌超微结构进行了观察。结果显示:复合生物保鲜剂对腐败希瓦氏菌的MIC与MBC分别为1.6 mg/ml与3.3 mg/ml,且随着作用时间的延长,复合生物保鲜剂对腐败希瓦氏菌的生长有明显抑制作用;尤其经2倍最小杀菌浓度的复合生物保鲜剂处理后,细菌未出现对数生长期;菌液在260 nm处的吸光值明显升高,菌体细胞膜完整性受到破坏;菌体细胞中的碱性磷酸酶升高,菌体细胞壁通透性增大;菌悬液的电导率值明显增大,细胞膜稳定性受损。细菌超微结构观察发现,复合生物保鲜剂作用于菌体细胞后,菌体细胞开始出现皱缩、扭曲变形、表面粗糙和布满泡状物及细胞壁塌陷等现象。表明复合生物保鲜剂可以破坏细菌的细胞内环境和细胞膜稳定性,影响了细菌的正常生长;并且通过影响细菌对营养物质的吸收和代谢物的排出,最终导致菌体死亡。

Anti-bacterial mechanism of composite biological preservative against Shewanella putrefaciens

To study the antibacterial effect of composite biological preservative against predominant spoilage bacterium(Shewanella putrefaciens) on refrigerated Trichiurus haumela,minimal inhibitory concentration(MIC) and minimial bactericidal concentration(MBC) of composite biological preservative against Shewanella putrefaciens were determined by oxford plate assay,and the antibacterial kinetics,the growth curve,the cell membrane integrity,the stability of cell and ultra microstructure of Shewanella putrefaciens treated with composite biological preservative were studied.The MIC and MBC of composite biological preservative against Shewanella putrefaciens were 1.6 mg/ml and 3.3 mg/ml.With the extension of treating time,the effect of different concentrations of composite biological preservative against Shewanella putrefaciens were getting significant.After treated with two times-MBC composite biological preservative,the bacteria did not have the logarithm growth period,its absorbance value at 260 nm was greater than that of controll,and the integrity of cell membrane was destroyed.Meanwhile,the content of alkaline phosphatase(AKP) of bacteria cells were increased,the membrane permeability was amplified,the electrical conductivity was increased and the cell membrane stability of Shewanella putrefaciens undermined.The ultra microstructural observation showed that bacteria treated with composite biological preservative appeared to shrink and distort,with cell surface rough and covered with bubbles,and cell walls collapsing and so on.In conclusion,composite biological preservative could destroy the stability of bacteria intracellular environment and cell membrane,and inhibit the growth of bacteria.It could influence the absorption of nutrients and excretion of metabolites,leading to the death of the cell.