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How to promote the growth of Lactobacillus acidophilus in milk?

如何促进牛奶中嗜酸乳杆菌的生长？

基本信息

批准号：
14560228
负责人：
ITOH Takatoshi
金额：
$ 2.24万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Lactobacillus acidophilus group lactic acid bacteria is a dominant lactobacilli in the human intestinal tract, and expected as useful probiotic strains. However, they usually grow poorly in milk than other yogurt starter lactic cultures. Therefore, the factors relating with the growth rate of L.acidophilus in milk were investigated. The amount of the remaining non-protein nitrogen components in fermented reconstituted milk were parallel to the growth rate of the strains. The relationship between the protease activity and growth rate of L.acidophilus in milk were investigated. The strains in L.acidophilus group which can grow well in milk were known to secrete the exocellular proteases at early stage of the cell growth, and the activity was kept constant while further incubation period. The results indicated that the high exocellular protease producing strains can preferentially grow in milk, because the low molecular nitrogen components should be supplied through hydrolysis of milk proteins by bacterial own proteases.Addition of casein hydrolyzed by 3 proteases showed all positive promoting effects on the acid production. In particular, casein treated with Protease p (Amano enzyme, Japan) showed the highest effect. The results indicated that the addition of the enzymatically digested casein to milk is a very useful way to accelerate the growth of L.acidophilus.The co-culture of the S.thermophilus with some strain of L.acidophilus was known to promote the growth of the L.acidophilus in milk. It is suggested the presence of some symbiotic relationship between two strains and the co-culture is a possible method for the production of probiotic fermented milk using L.acidophilus.

嗜酸乳杆菌群乳酸菌是人体肠道中的优势乳杆菌，有望成为有用的益生菌菌株。然而，与其他酸奶发酵剂乳酸菌相比，它们在牛奶中的生长通常较差。因此，对影响牛奶中嗜酸乳杆菌生长速度的因素进行了研究。发酵复原乳中残留的非蛋白氮成分的量与菌株的生长速率平行。研究了牛奶中嗜酸乳杆菌蛋白酶活性与生长速率的关系。嗜酸乳杆菌组中能够在牛奶中良好生长的菌株已知在细胞生长的早期阶段就分泌胞外蛋白酶，并且在进一步的培养期间其活性保持恒定。结果表明，高产胞外蛋白酶菌株能够优先在牛奶中生长，因为低分子氮成分应通过细菌自身蛋白酶水解牛奶蛋白来提供。添加3种蛋白酶水解的酪蛋白对产酸均具有积极的促进作用。特别是用蛋白酶p（天野酶，日本）处理的酪蛋白显示出最高的效果。结果表明，在牛奶中添加酶消化的酪蛋白是加速嗜酸乳杆菌生长的非常有用的方法。嗜热链球菌与某些嗜酸乳杆菌菌株的共培养已知可以促进牛奶中嗜酸乳杆菌的生长。这表明两种菌株之间存在某种共生关系，共培养是利用嗜酸乳杆菌生产益生菌发酵乳的一种可能方法。