泡菜中低温乳酸菌的筛选及其特性研究

Screening of Low Temperature Lactic Acid Bacteria from Pickles and Characteristic Research

于10℃条件从四川泡菜中分离获得乳酸菌36株,经过产酸能力初筛、低温测试复筛以及低温乳酸菌界定后,得到2株耐冷性强,温度生长范围2~40℃的菌株。经系统鉴定菌株3m-1为植物乳杆菌,菌株8m-9为肠膜明串珠菌。10℃条件下,菌株3m-1和8m-9培养12 h后细胞生物量快速增加,发酵液p H值显著降低,36h时活菌数达109CFU/m L,168 h时其活菌数109CFU/m L,终p H值分别降至3.70和4.00。30℃条件下,菌株3m-1培养2 h后进入对数期,22 h进入稳定期,终p H值降至3.60以下,能耐p H 3.0的酸度和14%的盐含量,对发酵液中亚硝酸盐降解率高于98%,且不含氨基酸脱羧酶;菌株8m-9在培养4 h后进入对数期,16 h进入稳定期,终p H值降至4.00,在p H〈4.00或盐含量〉10%的环境中,生长受到抑制,对发酵液中亚硝酸盐降解率高于75%,且不含氨基酸脱酸酶。排除酸、过氧化氢等因素干扰后,菌株3m-1和8m-9离心发酵上清液对指示菌藤黄微球菌仍有抑菌作用,用胰蛋白酶、木瓜蛋白酶处理后活性丧失,说明其抑菌物质是细菌素。本结果为低温乳酸菌的深入研究和低温发酵泡菜生产提供了重要菌种资源和理论依据。

Two cold tolerance lactic acid bacteria which could grow at temperature of 2-40 ℃, was screened from36 strains which were isolated from pickles in Sichuan, by strong acid-producing capacitices screening, low temperature properties screening and definition of low temperature lactic acid bacteria, the 3m-1 was finally identified as Lactobacillus plantarum and the 8m-9 was identified as Leuconostoc mesenteroides. Under 10℃ condition, cell biomass increased rapidly and the p H of fermentation broth decreased significantly after 12 h of inoculation of 3m-1 and 8m-9, its viable bacteria counts can reach 109CFU/m L at 36 h and retained 109CFU/m L at 168 h, the p H value were 3.70 and 4.00,respectively. Under 30 ℃ condition, 3m-1 entered logarithm phase after 2 h of inoculation, and stability phase after 22 h, the p H value was below 3.6, could grow in the condition in which the p H was higher than 3.0 or the salty concentration was lower than 14%, the nitrite degradation rate of fermentation broth was more than 98% and no decarboxylase activity, while 8m-9 entered logarithm phase after 4 h of inoculation,and stability phase after 16 h, the p H value was below 4.0, the growth of it was prevented in the condition in whice the p H was lower than 4.0 or the salty concentration was higher than 10%, the nitrite degradation rate of fermentation broth was more than 75% and no decarboxylase activity. After eliminating the interference of organic acid and hydrogen peroxide, the broth supernatant of 3m-1 and8m-9 still exhibited significant effects on bacteriostasis against Micrococcus luteus, after being treated by trypsin and papain, the microbiostatic activity of broth supernatant was decreased, which indicated that the bacteriostat was bacteriocin.The present results provided an important strain resource and theoretical basis for further study low temperature lactic acid bacteria and produce pickles in low temperature.