ESTABLISHMENT OF A DEFINED MINIMAL MEDIUM AND ISOLATION OF AUXOTROPHIC MUTANTS FOR BIFIDOBACTERIUM BIFIDUM ES 5

A perfectly defined minimal medium for strain Es 5 of Bifidobacterium bifidum was established. It consists of 3.5% D-(+)-lactose, 2.5% sodium acetate, 0.2% ammonium acetate, 0.25% dipotassium phosphate, 50μg/ ml riboflavin, 50μg/ml D-pantethine, 50ng/ml biotin, 0.3% potassium pyruvate, 0.1% L-cysteine-HCl, 0.5mM MgCl+2, 1mM FeCl2, 0.5μM MnCl2 and 50μM CaCl2 (pH 6.6).Many auxotrophic mutants were isolated from the strain using this minimal medium.