| 摘要: |
| 为筛选耐消化道逆环境的优良双歧杆菌菌株，以来源于母乳婴儿粪便、未断奶仔猪粪便、市售双歧杆菌制剂和本实验室保存的双歧杆菌为出发菌株，采用改良MRS液体培养基，模拟人体胃肠道逆环境，对其耐消化道逆环境特性进行了研究。通过耐酸（pH3的PBS）、耐胆汁酸盐（质量浓度1～20mg／mL）试验对初筛得到的14株菌株进行复筛，得6株菌株，它们在pH3条件下作用120min后存活率均〉93％，活菌数均〉100cfu／mL；在含5mg／mL牛胆酸钠的改良MRS液体培养基中作用24h后活菌数仍〉10^6cfu／mL，除J12和B03外，其他4株在含20mg／mL牛胆酸钠的改良MRS液体培养基中作用24h仍有活菌被检出（活菌数〉100cfu／mL）。在此基础上，采用胃蛋白酶和胰蛋白酶模拟胃肠液得3株耐消化道酶菌株A03、A04和L-1，在含5mg／mL胃蛋白酶的PBS培养基（pH3）作用120min后其活菌数均高达约100cfu／mL，而在含10mg／mL胰蛋白酶的改良MRS液体培养基作用24h后，其活菌数均高达约10^9cfu／mL；这2种消化道酶对其几乎没有抑制作用。研究结果表明，双歧杆菌A03、A04和L-1菌株耐受消化道逆环境的能力最好，可用做微生态制剂菌株。 |
| 关键词: 双歧杆菌 消化道 耐性 筛选 |
| DOI：10.11841/j.issn.1007-4333.2005.02.031 |
| 投稿时间：2004-09-23 |
| 基金项目:国家863计划资助项目（2002AA248041） |
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| Isolation of novel Bifidobacterium strains with tolerance of gastrointestinal environment |
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| Abstract: |
| A large culture collection of bifidobacteria (61 strains) was screened or activated from infant fecal samples, un-ablactated pig fecal samples, biotechnological preparations and Bifidobacterium strains conserved in the lab. Using CMRS medium, the intolerance ability of Bifidobacterium strains was studied in imitating gastroenteric environments. Fourteen strains were gained by the first screening; whereas only six obtained by the second screening (pH3 PBS, 1-20mg/mL bile salt concentration). Their survivability was above 93% and the living bacterial number was above 108cfu/mL after in pH3 condition and above 106cfu/mL after 24 h in 5mg/mL bile salt CMRS. Furthermore, B02, A03, A04 and L-1 could survive at 2g/kg bile salt (>104cfu/mL). Ultimately A03, A04 and L-1 show more longanimous to pepsin and pancreatin than others. The living bacterial number was about 108cfu/mL after 1.5 h in simulative gastric juice containing 5mg/mL pepsin, and was about 109cfu/mL after 24 h in simulative intestinal juice containing 1% pancreatin. The result shows that gastrointestinal tract tolerance ability of different Bifidobacterium strains was different; the tolerances of A03, A04 and L-1 were excellent ones among the tested strains, which have a latent ability as the strains of Mirobial Ecological Agents. |
| Key words: Bifidobacterium gastrointestinal tract tolerance ability isolation |
