Cholesterol Removal from Media by Lactococci

Abstract

Elevated serum cholesterol in humans is generally a risk factor correlated with the development of coronary heart disease. It has been reported that a culture of Lactobacillus acidophilus actively taking up cholesterol from a laboratory medium would function in vivo to exert a hypocholesterolemic effect. In the present study, seven strains of the genus Lactococcus were examined for their ability to remove cholesterol from laboratory media during growth. All strains of lactococci tested could remove cholesterol from media without degrading cholesterol. The amount of cholesterol removed was strain specific. Among them, Lc. Lactis subsp. lactis biovar diacetylactis N7 could remove as much cholesterol as L. acidophilus ATCC 43121, which had a beneficial influence on serum cholesterol levels in pigs. The manner of cholesterol removal by strain N7 corresponded to the manner of its growth. The growth of strain N7 (growth yield and growth efficiency) was enhanced. The fatty acid composition of the cells of strain N7 was altered by removing cholesterol from the media. The ability to remove cholesterol was also observed in the heat-killed cells of strain N7. However, the amount of cholesterol removed by the cells during growth was significantly higher than that removed by the heat-killed cells. Thus, strain N7 has the ability to remove cholesterol from media independently of whether cells are viable. These results indicate that administration of strain N7 in vivo may well be promising on the hypocholesterolemic effect.

Cholesterol reduction in vitro by novel probiotic lactic acid bacterial strains of Enterococcus isolated from healthy infants stool

“…Apparently, cholesterol reduction varied among the tested bacterial strains ranged from 48.22 to 71.6% reduction from the initial cholesterol concentration and the highest reduction mean values of 71.6 and 68.38% were obtained by the two isolates Y1 and W7, respectively. The results in the present study are in accordance with the experimental findings of Sieladie et al (2011) who reported that about 11 lactobacilli strains isolated from raw cow milk exhibited cholesterol Kimoto et al (2002). It has been reported that cholesterol removal by lactic acid bacteria appeared not to be the only strain specific but also growth dependent, as shown by studies that have evaluated cholesterol removal by probiotic cells during different growth conditions (Kimoto et al, 2002).…”

“…Different mechanisms for cholesterol removal by probiotics have been reported, such as deconjugation of bile salts by bile-salt hydrolase (BSH) (Ahn et al, 2003), cholesterol absorption into bacterial cell membranes (Kimoto et al, 2002), production of short-chain fatty acids (SCFAs) during the probiotics growth (Trautwein et al, 1998), and cholesterol transformation into coprostanol (Lye et al, 2010). Additionally, several cultural conditions such as media composition, pH, temperature, and inoculum size may change the metabolic pathways by altering pyruvate metabolism and external electron acceptors resulted in different end-products (Axelsson, 1998;Annuk et al, 2003).…”

Hypocholesterolaemic Effects of Probiotics

“…They also observed that assimilation occurred both at pH 6.0 and without pH control. Similar results have been reported for bifidobacteria [73] and lactococci [28]. Kimoto et al [28] observed that both live and heat-killed Lactococcus lactis subsp.…”

“…Similar results have been reported for bifidobacteria [73] and lactococci [28]. Kimoto et al [28] observed that both live and heat-killed Lactococcus lactis subsp. lactis biovar diacetylactis N7 were able to remove cholesterol from growth media.…”

“…Deconjugation of bile salt by the bile salt hydrolase (BSH) enzyme and subsequent co-precipitation of cholesterol at acidic pH is one of the models frequently used to explain hypocholesterolaemic effects of probiotics [21,23]. Other studies have shown reduction of cholesterol through assimilation of cholesterol into bacterial cell membrane [24][25][26][27][28], adhesion of cholesterol onto bacterial cell surface [28] and through the binding of bile acids to bacterial exocellular polysaccharides [29]. A recent study showed the ability of probiotics to be able to produce protein(s) with cholesterol-lowering effect [30].…”