The results suggested that L. fermentum SM-7 is a potential probiotic bacterium with cholesterol-lowering effects.

Aims:  To isolate new lactobacilli strain with cholesterol‐lowering effect and analyse its probiotic properties and possible mechanisms of cholesterol removal. Methods and Results:  The strain with cholesterol‐lowering effect was isolated from pickled juice. The acid and bile tolerance and antimicrobial activity were tested. The free cholalic acid, the cholesterol in supernatant fluid, washing buffer and cell extract, the cholesterol removed by growing, dead and resting cells were quantified. The isolated strain with high cholesterol‐reducing rate of 43·95% was identified as Lactobacillus buchneri (Lact. buchneri) P2. It had acid and bile tolerance and antimicrobial activity. Moreover, it could remove cholesterol via coprecipitating with deconjugated bile salts, assimilating and adsorbing by cells. And the assimilation was considered to be the main reason of cholesterol removal. Conclusions:  The isolated Lact. buchneri P2 showed probiotic properties of cholesterol reduction, acid and bile tolerance and antimicrobial activity and could remove cholesterol via different ways. Significance and Impact of the Study:  A new strain of Lact. buchneri P2 with efficient cholesterol‐reducing ability was isolated to provide species diversity of lactobacilli for functional dairy products. And the possible mechanism of cholesterol removal by Lact. buchneri was discussed.

In this study, Lactobacillus fermentum (L. fermentum) F1 reduced cholesterol 48.87%. The strain was screened from cattle feces using an API 50 CHL system and the 16S rRNA sequence contrasting method. L. fermentum F1 showed acid and bile tolerance, and antimicrobial activity against pathogenic Escherichia coli and Staphylococcus aureus. L. fermentum F1 deconjugated 0.186 mM of free cholalic acid after it was incubated at 37°C in 0.20% sodium taurocholate (TCA) broth for 24 h. Heat-killed and resting cells of L. fermentum F1 showed small amounts of cholesterol removal (6.85 and 25.19 mg/g, respectively, of dry weight) compared with growing cells (33.21 mg/g of dry weight). The supernatant fluid of the broth contained 50.85% of the total cholesterol, while the washing buffer and cell extracts had 13.53 and 35.39%, respectively. These findings suggest that L. fermentum F1 may remove cholesterol by co-precipitating with deconjugated bile salt, assimilating with cells and by incorporation into cellular membranes. Cholesterol assimilated by cells held 72.0% of the reduced cholesterol, while 21.65% of the reduced cholesterol was coprecipitated with deconjugated bile salt and 5.89% was adsorbed into the surface of the cells.