FIG. 4.
Growth of L. lactis in CDM containing αs1-casein (A), β-casein (B), or κ-casein (C) and supplemented with different mixtures of amino acids as nitrogen sources. Solid bars, L. lactis MG611-1 (PI-type proteinase); open bars, L. lactis SH5-1 (PIII-type proteinase). 6, mixture of His (H), Ile (I), Gln (Q), Val (V), Leu (L), and Met (M); 6-X, mixture lacking amino acid X. The amino acid concentrations were the amino acid concentrations in CDM (27), and the casein concentration was 2.4 g/liter. Error bars indicate confidence limits at P = 0.95. Asterisks indicate that no growth occurred.