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Nutritional Requirements and Biochemical Activities of Brewery Lactobacilli
Abstract
Summary: Four strains of lactobacilli, isolated from the contaminant flora of English top fermentation brewers’ yeasts, were found to be heterofermentative. Two strains were tentatively identified as Lactobacillus brevis. For growth, all the strains required exogenous supplies of a number of growth factors of the vitamin B complex, a pyrimidine, at least one purine and at least 14 amino acids. The ability of hypoxanthine to substitute for both adenine and guinane in one strain of L. brevis is especially notable. l-Arginine, essential for the growth of all strains, increased the rate and final amount of growth in glucose medium of both strains of L. brevis, when it was supplied in relatively high concentration. Suspensions of the organisms converted arginine into ornithine, ammonia and a small amount of citrulline. Maltose, fructose and l-arabinose were better substrates for the growth of all strains than glucose, which, as major source of energy, supported little or no growth of the two unidentified strains. All the strains transformed fructose into mannitol. The rate and extent of growth of most strains on hexoses and the rate of growth of all strains on maltose were increased by the presence of acetate. Whereas the strains of L. brevis formed only little acid from glucose, all strains produced considerable amounts of volatile and non-volatile acids from l-arabinose.
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© Society for Gerenal Microbiology, 1955