来宾酒糟酸菜中降胆固醇乳酸菌的筛选鉴定及发酵工艺研究

该研究采用钙溶圈法及MRS-胆固醇培养基从来宾酒糟酸菜汁中分离筛选具有降胆固醇能力的乳酸菌，通过形态观察及分子生物学技术对其进行菌种鉴定，同时对其耐酸性、耐胆盐性能进行研究，并以胆固醇去除率为考察指标，通过单因素试验及正交试验对其发酵条件进行优化。结果表明，筛选得1株具有去除胆固醇能力的乳酸菌，编号为XL-02，经鉴定，菌株XL-02为植物乳杆菌（Lactobacillus plantarum），其具有较好的耐酸能力和胆盐耐受性。在pH2.0的酸性环境下培养24 h，菌株存活率为3.14%；在胆盐含量为0.3%条件下培养24 h，菌株存活率为12.17%。菌株XL-02去除胆固醇的最优发酵条件为以MRS液体培养基为发酵培养基，初始pH值6.0，接种量4%，发酵温度39 ℃，发酵时间72 h。在此优化条件下，胆固醇去除率为（61.56±0.08）%。

Screening,identification and fermentation technology of cholesterol-lowering lactic acid bacteria from Laibin distiller's grains pickled vegetables

In this study, a lactic acid bacterium with cholesterol-lowering ability was isolated from Laibin distiller's grains pickled vegetables by calcium dissolving zone and MRS-cholesterol medium, and was identified by morphological observation and molecular biology techniques. The acid resistance and bile salt resistance were studied, and using cholesterol removal rate as response value, the fermentation conditions were optimized by single factor and orthogonal experiments. The results showed that a strain of lactic acid bacteria with cholesterol-removing ability was screened, and numbered XL-02, which was identified as Lactobacillus plantarum with excellent acid resistance and bile salt tolerance. The survival rates of the strain cultured for 24 h in the acidic environment with pH 2.0 and the condition of bile salt content 0.3% were 3.14% and 12.17%, respectively. The optimal fermentation conditions for strain XL-02 to remove cholesterol were MRS liquid medium as fermentation medium, initial pH 6.0, inoculum 4%, fermentation temperature 39 ℃ and time 72 h. Under the optimized conditions, the cholesterol removal rate was (61.56±0.08)%.