【摘要】 对乳酸菌素产生菌进行分离,得到4株理想菌株。利用高效液相色谱检测其发酵液,初步确定4菌株均为乳酸菌,其中Ⅱ32菌株产乳酸最多,对各指示菌的抑制作用最显著,对该菌株作进一步的研究。Ⅱ32菌株在MRS培养基上可以生长,最适生长温度为28℃,革兰氏染色呈阳性,无芽孢。通过API生化反应实验、16SrDNA测序可进一步确定该菌株是L·paraplantarum或L·paraplantarum。最终通过对recA-gen的PCR产物检测,鉴定菌株Ⅱ32为Lactobacillusparaplantarum(类植物乳杆菌)。牛津杯抑菌试验显示,该菌株的发酵液不仅对多数G+细菌的生长有较强的抑制作用,而且对大肠杆菌、沙门氏菌等Gˉ细菌的生长也具有明显的抑制作用,但对真菌没有活性。更多还原

【Abstract】 Lactic acid bacteria were isolated from fermented food and screened for bacteriocin production. Four strains with higher antibacterial activity and lactic acid productivity were oblained. These strains were analyzed by HPLC and strain Ⅱ32 showed the strongest antibacterial activity. The stain Ⅱ32 was gram-positive and non-sporing. It grew in MRS media and the optimum temperature was 28 ℃. The strain was further characterized by its carbohydrate fermentation pattern using the API 50 CH system and the sequence of the cloned 16S rDNA fragments. Ultimately, strain Ⅱ32 was identified as Lactobacillus paraplantarum by amplification of PCR recA-gene. Strain Ⅱ32 showed powerful inhibitory activity against not only Gram-positive bacteria but also Gram-negative bacteria such as Escherichia coli,Salmonella sp. However, the strain has no antimicrobial activity against fungi.更多还原