一株曲拉源短乳杆菌的分离及其体外抑菌特性分析

摘要：目的 天然牦牛乳曲拉中蕴含着大量的乳酸菌,为丰富食品发酵的有益菌种资源,本试验分离筛选具有抑菌活性的乳酸菌。方法 以西藏牦牛乳曲拉为分离基质,MRS(De Man Rogosa Sharpe)加上1%CaCO3为选择鉴别培养基,运用形态学观察、生理生化试验、16S r RNA基因序列、药敏试验对分离菌株进行菌种鉴定,通过抑菌试验探究其抑菌活性。结果 分离菌株NWMCC0322被鉴定为短乳杆菌,其对青霉素类、四环素类、大环内酯类、酰胺醇类、喹诺酮类、磺胺类、头孢类药物敏感,对多烯类药物中敏。NWMCC0322对指示菌金黄色葡萄球菌的抑菌效果最好,其抑菌圈直径达12.0±0.6 mm,其次为甲型副伤寒沙门氏菌11.3±0.3 mm,大肠杆菌11.0±0.5 mm。结论 该短乳杆菌对食品污染常见菌株具有抑菌效果,在食品发酵中有较好的应用价值。

Isolation of a strain of Lactobacillus brevis from Qula and analysis of its antibacterial properties in vitro

Abstract: Objective Natural yak Qula contains a large number of lactic acid bacteria, to enrich the beneficial strain resources of food fermentation, this experiment isolated and screened lactic acid bacteria with antibacterial activity. Methods Tibetan yak lactotrela was used as isolation medium, De Man Rogosa Sharpe (MRS) and 1%CaCO3 was used as identification medium. Morphological observation, physiological and biochemical test, 16S rRNA gene sequence and drug sensitivity test were used to identify the isolates. Results The isolated strain NWMCC0322 was identified as Lactobacillus brevis. It was sensitive to penicillins, tetracycline, macrolides, aminools, quinolones, sulfonamides and cephalosporins, and sensitive to polyene drugs. NWMCC0322 had the best bacteriostatic effect on indicator bacteria Staphylococcus aureus, and its bacteriostatic zone diameter was 12.0±0.6 mm, followed by Salmonella paratyphi A 11.3±0.3 mm, Escherichia coli 11.0±0.5 mm. Conclusion The Lactobacillus brevis has antibacterial effect on common strains of food contamination and has good application value in food fermentation.