通过微生物分离和鉴定从浙东传统腌冬瓜中得到4株优势菌，分别为植物乳杆菌（Lz151）、发酵乳杆菌（Lz152）、棒状乳杆菌（Lz153）和戊糖乳杆菌（Lz154），通过酶学分析方法对4株乳酸菌的产生乳酸脱氢酶、亚硝酸盐还原酶、酯酶和转氨酶的特性进行研究。实验表明，4株乳酸菌都有乳酸脱氢酶、亚硝酸盐还原酶、酯酶和转氨酶活性，植物乳杆菌和发酵乳杆菌有较高的乳酸脱氢酶活力，分别达到122.34 U/mL和113.56 U/mL；发酵乳杆菌和戊糖乳杆菌有较高的亚硝酸盐还原酶活性，分别为17.62 U/mL和13.42 U/mL，而棒状乳杆菌具有最低的亚硝酸盐还原酶活力，为4.74 U/mL；植物乳杆菌和棒状乳杆菌比其他两种乳酸菌有较高的酯酶活性，达到11.53 U/mL和13.78 U/mL。此外，植物乳杆菌和戊糖乳杆菌有较高的转氨酶活性，分别为25.37 U/mL和23.19 U/mL。4株乳酸菌产酶的最适温度和pH存在菌种间差异，而且同一株菌产生各种酶的最适条件也不同，分离乳酸菌分别在30 ℃、35 ℃、40 ℃产各种酶的能力最高，而发酵乳杆菌、植物乳杆菌的最适产酶pH分别为6.0、7.0。

By isolation and identification of microorganisms in traditional pickled wax gourd from eastern Zhejiang, four dominant lactic acid bacteria (LAB) strains were obtained which were Lactobacillus plantarum (Lz151), Lactobacillus fermentum (Lz152), Lactobacillus coryniformis (Lz153), and Lactobacillus pentosus (Lz154). The characteristics of all strains to produce lactate dehydrogenase, nitrite reductase, esterase, and aminotransferase were analyzed by enzymological methods. The results showed that the four strains presented the lactic dehydrogenase, nitrite reductase, esterase, and aminotransferase activities. Lactobacillus plantarum and Lactobacillus fermentum showed relatively high lactic dehydrogenase activity. The values reached 122.34 U/mL and 113.56 U/mL, respectively. Lactobacillus fermentum and Lactobacillus pentosus presented relatively high nitrite reductase activity. The values reached 17.62 U/mL and 13.42 U/mL, respectively. Lactobacillus coryniformis possessed the lowest nitrite reductase activity (4.74 U/mL). Compared with the other two strains, Lactobacillus plantarum and Lactobacillus coryniformis displayed higher esterase activity. The values reached 11.53 U/mL and 13.78 U/mL, respectively. Moreover, Lactobacillus plantarum and Lactobacillus pentosus exhibited higher aminotransferase activity, whose values were 25.37 U/mL and 23.19 U/mL, respectively. Inter-strain differences were presented in the optimal enzyme-producing temperature and pH among the four strains and the optimum conditions for the same strain to produce various enzymes were different. The optimum temperatures for the isolated LAB strains to produce various enzymes were 30?C, 35?C, and 40?C, respectively. The optimal enzyme-producing pH values of Lactobacillus fermentum and Lactobacillus plantarum were 6.0 and 7.0, respectively.

国家自然科学基金（31171735）；宁波市农业择优委托项目（2012C10016）