Culture media formulation for metabolic studies of lactic acid bacteria

FABIANA M. SAGUIR AND MARÍA C. MANCA DE NADRA

Nitrogen Compounds Metabolism by Lactic Acid Bacteria

Transworld Research Network

Lugar: Kerala, India; Año: 2008; p. 2 - 23

Due to nutritional complexity of lactic acid bacteria (LAB), they are frequently cultivated in complex or natural media containing energy sources, precursors and stimulatory substances for cell growth and division. However the complexity of these media such as MRS o M17 cannot be used to characterize precisely the nutritional requirements of LAB. Moreover the consumption of the various intermediary metabolites for biosynthesis of macromolecules via the anabolic pathways cannot be correctly established when using complex organic compounds, because they provoke considerable uncertain in these studies. Synthetic media sufficiently simple to allow full carbon balance is therefore an essential step in the study of nitrogen metabolism of LAB. The use of a chemically defined medium is also important to enhance the proteinase activity by termophilic lactobacilli and to study the regulation of this enzyme. Different investigations concerning to development of synthetic media for an optimal LAB growth have been carried out. A simple synthetic medium was development for sustained growth of Lactococcus lactis for at least 50 generations of cell division. In this medium growth was not perturbed by the suppression of the ammonium ion component. This fact indicates that the limited number of amino acids retained in the simplified defined medium could supply the entire nitrogen requirement of the cell. Recently a chemically defined medium for lactobacilli growth was improved mainly of the basis of annulling limitations with respect to amino acids. In addition increments of some vitamins produce the best bacterial growth in the formulated medium, for the sustained growth of Lactobacillus plantarum strains. This medium is proposed for conducting metabolic and genetics studies of LAB. correctly established when using complex organic compounds, because they provoke considerable uncertain in these studies. Synthetic media sufficiently simple to allow full carbon balance is therefore an essential step in the study of nitrogen metabolism of LAB. The use of a chemically defined medium is also important to enhance the proteinase activity by termophilic lactobacilli and to study the regulation of this enzyme. Different investigations concerning to development of synthetic media for an optimal LAB growth have been carried out. A simple synthetic medium was development for sustained growth of Lactococcus lactis for at least 50 generations of cell division. In this medium growth was not perturbed by the suppression of the ammonium ion component. This fact indicates that the limited number of amino acids retained in the simplified defined medium could supply the entire nitrogen requirement of the cell. Recently a chemically defined medium for lactobacilli growth was improved mainly of the basis of annulling limitations with respect to amino acids. In addition increments of some vitamins produce the best bacterial growth in the formulated medium, for the sustained growth of Lactobacillus plantarum strains. This medium is proposed for conducting metabolic and genetics studies of LAB.