耐高温乳酸菌的分离与鉴定

Isolation and Identification of Thermotolerant Lactic Acid Bacteria

目的:本实验从不同地方采集的青贮玉米饲料、果渣、牛奶、新鲜的泡菜汁等样品中筛选耐高温乳酸菌。方法:通过初筛、复筛,获得一株耐高温且产酸能力较强的菌株L1;依据伯杰氏系统细菌学手册和乳酸菌分类鉴定的标准和描述,对其进行了生理生化特性鉴定;通过单因素试验和正交试验确定菌株L1的最佳发酵条件。结果:确定其为乳杆菌属德氏乳杆菌;最佳增殖培养基组分为:玉米粉16%+麸皮5%;在α-淀粉酶(5U/g玉米粉、90℃、30min)和糖化酶(150U/g玉米粉、55℃、2h～3h)酶解作用下,最佳发酵条件为:发酵温度60℃,发酵时间36h,pH值3.5。结论:经过初筛、复筛获得一株耐高温菌株L1,通过糖发酵等生理生化试验、正交试验鉴定,最后确定此菌株为乳杆菌属德氏乳杆菌(LacotobaciLLus deLbbruecki)。

Objective：To isolate lactic acid bacteria with high thermotolerance from silage,apple pomace,milk and fresh pickles. Methods- A strain LI with thermotolerace and producing more lactic acid was isolated through the primary and secondary screening, According to the criteria and description of Bergey＇s manual of systematic bacteriology and classification and identification of LAB, the strain L1 was done the physiological and biochemical tests. Through the single factor experiments and orthogonal test, we knew the optimal cultural conditions of the strain L1. Results： The optimal cultural conditions of the strain L1 was as follows： the optimal composition of culture medium was 16 % corn flour ＋ 5 % bran. culture temperature being 60℃ and culture time being 24 h at the enzymolysis of α - amylase （90 ℃ ,30 min,5 U/g corn） and saccharifying enzyme（55 ℃ ,2 h - 3 h,150 U/g）. final pH being 3.5. Conclusion：A strain LI with thermotolerace a was isolated through the primary and secondary screening. The strain L1 is LacotobaciLLus deLbbruecki by the physiological and biochemical tests, orthogonal test.