Microbial Reduction of Cholesterol by Lactic Acid Bacteria and Eubacterium sp.

The objective of this study was to examine the cholesterol degrading ability of a Eubacterium sp., several L. acidophilus and other lactic acid bacteria under anaerobic conditions in order to find more efficient microorganism in degrading cholesterol.Lactobacillus strains and Eubacterium sp. Were grown in Bennet\u27s medium supplemented with 0.05% (w/v) polyoxyethanylchole steryl sebacate (water soluble cholesterol) and basic cholesterol medium, respectively, at 30°C for 7 days under anaerobic condition. Cholesterol content, pH values and total colony counts of the samples were analysed after 0, 3, and 7 days. The effect of initial pH (6.0-8.0) of the medium on the cholesterol degrading activity of Lactobacilli was also studied. The most active strains under anaerobic conditions were used for further testing in phosphate buffer containing beef tallow or ground beef. Results from this study indicated that several strains of lactic acid bacteria were capable of degrading cholesterol anaerobically. Approximately 25 to 40% of the cholesterol supplied in Bennet\u27s medium was reduced by L. acidophilus AS (38.4%), L. acidophilus L32LP (34.7%), L. acidophilus JO (32.3%), L. acidophilus JM (28.3%) and L. acidophilus ATCC 521 (25.8%) after 3 days of incubation. After 7 d of incubation, cholesterol was reduced by L. viridescens ATCC 12706 (45.3%), L. leichmanniiATCC 7830 (37.6%), L. acidophilus LPA (32.3%), L. acidophilus LPM (28.5%), and L. acido philus (27.5%). The initial pH values of the medium affected the extent of cholesterol degradation. The pH values of 7.0 and 8.0 resulted in greater degradation than the pH value of 6.0. Under experimental conditions, cholesterol in beef tallow could be degraded (net reduction) by Eubacterium sp. (8.9%), L. acidophilus L32LP (18.5%), and L. leichmannii ATCC 7830 (11.6%). The cholesterol content of ground beef was reduced (net reduction) only by L. leichmannii ATCC 7830 (10.5%)