Abstract

Lactococcus lactis from yoghurt sample was confirmed based on alignment of 16S rRNA gene sequence in gene bank. The degree of acid and bile tolerance of strain L. lactissubsp. lactis KF147 was evaluated. The L. lactis KF147 was able to maintain viability for 2 h at pH 2 and growth in a medium with 0.4% (w/v) of bile acids. The maximum cholesterol reduction was 66.8% from the mMRS culture medium supplemented with 100 mg/L cholesterol. The tested strain was capable of binding cholesterol and removing 13% cholesterol from the medium. The growth of bacteria was affected by the presence of cholesterol in the medium. The growing bacterial cells had cholesterol reducing activity more than resting and dead cells. Transmission electron microscopy and IR analysis detected the cholesterol binding activity between L. lactis KF147 cells and the cholesterol. The fatty acid composition of the cells of L. lactis KF147 was altered by reducing cholesterol from the MRS medium that indicated incorporation of the cholesterol particles into cell membrane. According to these results, L. lactis KF147 revealed the probiotic potential in hypocholesterolemic effect on rats.

Key words: Cholesterol reduction, cholesterol binding, probiotic, hypocholesterolemic,Lactococcus lactis KF147.