A Synthetic Medium for Comparative Nutritional Studies of Lactobacilli

Abstract

The composition of a synthetic medium supporting the growth of lactobacilli is given (Table 1). The medium, containing glucose, amino acids, vitamins, mineral salts, purines and pyrimidines, allows the study of nutritional requirements of different strains of lactobacilli under identical environmental conditions. It was found that all the strains tested needed L‐glutamic acid, L‐valine and L‐leucine, and a group of them also required L‐arginine, L‐tyrosine and L‐tryptophan. Some strains required vitamins, e.g. L. bulgaricus (pantothenic acid), L. fermenti (pantothenic acid and niacin). These results are compared with those found by others employing different media.

Production of conjugated linoleic acid by dairy starter cultures

“…For instance, MRS broth contained 0·1% Tween-80, while skim-milk contained 3% milk protein. The growth stimulation property of Tween-80 and its properties of neutralization of the antimicrobial effect of fatty acids have been well demonstrated in the past (Dubos 1947;Ledeoma et al 1977;Baker et al 1983;Cummins and Johnson 1986). Furthermore, the presence of proteins can also counteract the inhibition of fatty acids (Dubos 1947;Boyaval et al 1995).…”

Contribution of the phosphoenolpyruvate:mannose phosphotransferase system to carbon catabolite repression in Lactobacillus pentosus

“…During all the experiments described in this study, cells were cultivated on the Lactobacillus synthetic rich MCD medium (Lauret et al, 1996), supplemented with 50 mg l − " each of -aspartic and -glutamic acid, which are essential amino acids for species related to Lactobacillus plantarum (Ledesma et al, 1977). All carbohydrates were added at a final concentration of 0n5% (w\v) and erythromycin (5 µg ml − ") was added when necessary.…”

Effects of free fatty acids on propionic acid bacteria

“…ln this study we were unable to detect any positive effect of the polyoxyethylene derivative of fatty acid monoesters of sorbitan (ester of oleic acid = Tween 80; ester of stearic acid = Tween 60 and ester of palmitic acid = Tween 40) at 100 mg 1-1 on the growth of P freudenreichii subsp shermanii LRTL 30. This growth stimulation was frequently evidenced in the past (Dubos, 1947;Ledeoma et al, 1977;Cummins and Johnson, 1986). The neutralization of the antimicrobial properties of Iinoleic acid by Tween 80 at 30 9 1-1 was also evidenced by Baker et al (1983) for laurie acid.…”