选用18株乳酸菌和1株标准菌株植物乳杆菌1.2158(Lactobacillus plantarum1.2158)进行葡萄糖产酸产气实验和hot-loop实验,以探讨异型乳酸菌两种常用鉴定方法的异同。结果如下:(1)葡萄糖产酸产气法的检测结果表明,实验菌株产酸能力不同。实验菌株中有7个形成明显的琼脂柱位移,鉴定为异型乳酸菌,占总菌株量的36.8%;(2)hot-loop法检测结果表明有13个菌株形成气泡或柱状泡泡,鉴定为异型乳酸菌,占总菌株量的68.4%;(3)菌株L-6、L-14、L-15、L-16、L-18和L-19为葡萄糖产酸产气法和hot-loop法共同检测出的异型乳酸菌株;L-5为葡萄糖产酸产气法检测出的特异异型乳酸菌株;L-1、L-2、L-3、L-7、L-8、L-9和L-17为hot-loop法检测出的特异异型乳酸菌株。hot-loop法具高灵敏度,但葡萄糖产酸产气法具观察菌株产酸能力的方便性和判断菌株产气的直观性;葡萄糖产酸产气法和hot-loop法检测的异型乳酸菌株有互补性。将两种方法进行结合应用,会使鉴定结果更具有有效性和快速性。

To find a better way of identifying the homo-or heterofermentative lactic acid bacteria(LAB),advantages and disadvantages of two common tests for detecting heterofermentative LAB were studied in the present study.The results are compared for 19 isolates and showed that:(1) the test of the acid and gas produced by the metabolization of glucose or gluconate showed the tested isolates had different ability to produce acid;also the test detected 7 heterofermentative LAB,which indicated that only 36.8% of the isolates was positive;(2) the hot-loop test showed the tested isolates formed gas evolution or a small stream of bubbles;also the test detected 13 heterofermentative LAB,which indicated that only 68.4% of the isolates was positive;(3) strains of L-6,L-14,L-15,L-16,L-18,and L-19 were identified as heterofermentative LAB by both of these two tests;L-5 strain was identified as heterofermentative LAB only by the acid and gas production by the metabolization of glucose or gluconate test;strains of L-1,L-2,L-3,L-7,L-8,L-9,and-17 were identified as heterofermentative LAB only by the hot-loop test.Therefore,the results showed that the hot-loop test was more sensitive.However,the test of the acid and gas produced by the metabolization of glucose or gluconate had the superiority to estimate the acid production of isolates,and this test was found to be more observable.Thus,it is better to combine these two methods together in the process of detecting the heterofermentative LAB.