四川泡菜中降解亚硝酸盐乳酸菌的筛选鉴定及其应用

从四川传统泡菜中分离疑似乳酸菌170株,通过溶钙力测定获得33株产酸力较强的菌株,然后对其进行亚硝酸盐降解力初筛试验,得到5株具有较强降解亚硝酸盐能力的菌株,再采用控制pH值的方法从中筛选出1株酶降解亚硝酸盐作用明显的菌株N2,该菌株按0.1%(v/v)接种量接种于含125 mg/L NaNO2、pH 6.4和添加有2%CaCO3(w/v)的MRS培养基中,于30℃、120 r/min振荡培养72 h,对NaNO2的降解率达90.81%。菌株N2经形态学、生理生化特征及16S rDNA序列分析被鉴定为植物乳杆菌(Lactobacillus plantarum)。接种菌株N2发酵泡菜,测定发酵过程中泡菜pH值、亚硝酸盐含量,与自然发酵泡菜比较,菌株N2应用于发酵泡菜中降解亚硝酸盐的效果显著。

Screening, identification and application of nitrite-degenerating lactic acid bacteria from Sichuan pickles

170 strains of lactic acid bacteria were isolated from Sichuan pickles.Among them,33 strains were selected for their excellent characteristics in acid production through the determination of calcium dissolving ability.Through the comparison of their nitrite degradation ability in MRS liquid medium,5 strains with higher nitrite degradation ability were selected.By controlling the pH of MRS liquid medium,strain N2 was approved to degrade nitrite quickly with enzymatic degradation.When it was grown by 0.1% inoculation amount in medium of pH 6.4 containing 125 mg/L nitrite sodium and 2% of CaCO3(w/v) at 30℃ and 120 r/min for 72 h,strain N2 could degrade 90.81% nitrite sodium.Strain N2 was identified as Lactobacillus plantarum by morphologic observation,biochemical identification and sequence analysis of 16S rDNA.The pH and nitrite concentration were measured on the spontaneous and inoculation fermented(with strain N2 as fermentation agent)cabbages.The results indicated that nitrite in sauerkraut could be degraded well by strain N2.