具降胆固醇功能的海洋源乳酸菌的筛选及 发酵条件工艺优化

Study on screening of cholesterol-lowering marine lactobacillus and optimization of fermentation conditions

本研究采用邻苯二甲醛法从柏式中喙鲸(Mesoplodon densirostris)内脏中筛选出一株具高效降解胆固醇功能的乳酸菌HJ-S2,利用16S rDNA分子生物学和API 50CH系统鉴定其为植物乳杆菌(Lactobacillus plantarum)。为提高乳酸菌HJ-S2体外降胆固醇能力,考察了菌株的生长特性,并从培养基条件和发酵条件两个方面,采用单因素和正交试验进行工艺优化。优化后的培养基条件为:蛋白胨含量5 g/L,葡萄糖含量25 g/L,胆固醇含量1.0 g/L,胆盐含量2.0 g/L;发酵条件为:温度37℃,pH 6,培养时间24 h,接种量1%。在此优化条件下,胆固醇降解率达到69.81%,较优化前有显著提升,为功能性益生菌制剂的开发应用提供生产工艺及参考依据。

A lactobacillus HJ-S2 with high effectiveness of cholesterol lowering was isolated from a beaked whale(Mesoplodon rostris)viscera using o-benzaldehyde method.The bacterium was identified as lactobacillus plantarum by 16S rDNA and API 50CH.In order to improve the cholesterol-lowering ability of HJ-S2 in vitro,the growth characteristics of the strain was investigated.Single factor and orthogonal experiment was used to optimize the condition in two aspects,the fermentation and medium.The optimized fermentation condition was set as follows:peptone 5 g/L,glucose 25 g/L,cholesterol 1.0 g/L,bile salt 2.0 g/L,temperature 37℃,pH 6,incubation time 24 h and inoculation amount 1%.Under the optimized condition,the cholesterol-lowering rate reached 69.81%,which significantly improved the result.Thus the optimized fermentation condition could offer production process and reference for further development in application of functional probiotics.