腐败发酵蔬菜中产膜醭细菌的分离鉴定及其生长特性分析

以发酵蔬菜为研究对象,分离和鉴定其中形成腐败膜醭的主要微生物,并分析其生长特性。利用胰蛋白胨大豆琼脂培养基分离培养发酵蔬菜腐败膜醭中的微生物,挑取50株单克隆回接到发酵盐卤胰蛋白胨培养基中培养,将能够在培养液表面显著形成膜醭的菌株进行16S rDNA或18S rDNA分子生物学鉴定。结果表明这6株菌均为细菌,分别为枯草芽孢杆菌、弗氏柠檬酸杆菌、科氏葡萄球菌科氏亚种、普罗威登斯菌、克雷伯氏杆菌属和阴沟肠杆菌。利用5种发酵蔬菜模拟培养基培养上述6株细菌,发现不同菌株在不同培养基中产膜醭情况不同。枯草芽孢杆菌和科氏葡萄球菌科氏亚种除了能形成膜醭外,还能引起培养基pH值升高,并对氮源需求不高。克雷伯氏杆菌属和普罗威登斯菌仅在发酵盐卤胰蛋白胨培养基和发酵蔬菜汁胰蛋白胨培养基中形成膜醭。上述细菌可能是发酵蔬菜腐败膜醭形成的关键细菌和潜在威胁。

Isolation,Identification and Growth Characteristic Analysis of Pellicle-Forming Bacteria from Spoiled Vegetable

The main microbes which could form pellicle in spoiled vegetable were isolated and identified. The growth characteristics of these microbes were also analyzed. Tryptone soy agar (TSA) medium was used to isolate the pellicleforming microorganisms. Fifty isolates were selected randomly from TSA medium and inoculated into tryptone soy broth medium supplemented with fermented brine (TFB). Six isolates which could form pellicle on the surface of the medium were subjected to 16S rDNA or 18S rDNA identification. The results showed that the pellicle-forming agents were all bacteria, which were identified as Bacillus subtilis, Citrobacter freundii, Staphylococcus cohnii subsp. cohnii, Providencia vermicola, Klebsiella sp. and Enterobacter cloacae. The pellicle-forming abilities of each isolate in different model media were different. Bacillus subtilis and Staphylococcus cohnii subsp. cohnii could also increase the pH value of the medium and had lower nitrogen requirement. Klebsiella sp. and Providencia vermicola could form pellicle only in TFB and TSA supplemented with squeezed juice from fermented vegetable (TFVJ). The bacteria described above might be the key agents for pellicle formation and pose a potential risk for fermented vegetable quality.