摘要
采用溶钙圈法和琼脂扩散法从传统发酵食品中筛选具有抑菌作用的菌株,通过形态学观察、生理生化反应和16S rDNA分析进行菌株鉴定,经过酶敏感性反应、排酸实验和HPLC检测对所产抑菌物质进行初步分析,采用琼脂扩散法对抑菌物质进行抑菌谱研究。结果显示,从东北酸菜中筛选到一株具有较强抑菌作用的植物乳杆菌(Lactobacillus plantarum)CNQ3,该菌株在MRS培养基中发酵24 h,活菌数为6.5×10~(11) CFU/mL,抑菌圈直径为19.50 mm。L.plantarum CNQ3所产抑菌物质表现为有机酸,HPLC检测其主要为乳酸和醋酸,二者含量分别为11.23和5.58 mg/mL,同时含有0.083 mg/mL的苯乳酸。该抑菌物质的抑菌谱广,对受试的8株食源性致病菌和腐败菌具有抑菌作用,其中对单核增生李斯特菌(Listeria monocytogenes)的抑菌效果最好,抑菌圈直径23.30 mm,对藤黄微球菌(Micrococcus luteus)的抑菌圈直径最小,为18.96 mm。本研究为筛选具有抑菌活性的乳酸菌提供参考价值。
The strain was isolated and screened from the traditional fermented food samples with the methods of dissolving calcium ring and agar diffusion inhibition circle. The strain identification was studied by physiological characterization observation,biochemical test and 16 S rDNA sequencing analysis. The analysis of antibacterial substances was carried out by enzyme sensitivity reaction,acid elimination test and HPLC detection. The antibacterial spectrum was investigated by the method of agar diffusion inhibition circle. The results showed that the strain DB was isolated from the northeast sauerkraut sample,and it was identified as Lactobacillus plantarum CNQ3.After fermentation for 24 h in MRS,the viable count of L. plantarum CNQ3 was 6.5×10~(11) CFU/mL and the diameter of inhibitory zone against Staphylococcus aureus was 19.50 mm. The antibacterial fermentation broth of L. plantarum CNQ3 was primarily determined as organic acids. The acid compounds were analyzed by HPLC and they were mainly presented as lactic acid and acetic acid,in which the contents were 11.23 mg/mL and 5.58 mg/mL,respectively,moreover,they also contained phenyllactic acid for 0.083 mg/mL. The active compounds showed a wider antibacterial spectrum with the tested foodborne pathogens and spoilage bacteria,in which,they exhibited the best antagonistic activity against Listeria monocytogenes,and the inhibitory zone diameter was 23.30 mm,while,the antibacterial effect was weak on Micrococcus luteus,which with an inhibitory zone diameter of 18.96 mm. This study provided a certain reference value for screening of LAB with antibacterial activity.
引文
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