Four kinds of lactobacillus for generating bilesalt hydrolase and extracellular polysaccharide and functionality yoghourt production technique thereof

The invention belongs to a production technology of four lactobacillus producing bile salt hydrolase and extracellular polysaccharide as well as functional yoghurt production technology. The technology is adaptable to the production of functional yoghurt and microbial ecological agents in fermented dairy products for lowering cholesterol. The technology adopts high throughput screening technique and an ortho-phthalaldehyde method to obtain bacterial strains which can efficiently reduce the cholesterol, to get the bacterial strains which can produce the bile salt hydrolase with high yield by an Oxford cup method and to gain the bacterial strains which can produce the extracellular polysaccharide with high yield by a phenol-sulfuric acid method. All the four kinds of screened lactobacillus have excellent fermentation performance. The yogurt with fine quality is prepared by lactobacillus casei KL1 (CGMCC No1809) and J1 (CGMCC No1808), which have the bile salt hydrolase with high efficiency in lowering the choles