FIGURE 4. (A) Variation of medium pH during cultivation of L. gasseri (□, ▪) in MRS alone or in combination with C. glabrata or C. albicans (○, •), under the same conditions as those used to obtain the growth curves shown in Fig. 1. In panel (B) the variations in the ratio of lactate/ lactic acid (LA)/ and acetate/acetic acid (AA) is shown along the single-species or co-cultivation settings, as estimated by the Handerson-Hasselbach equation and using the pHs determined in panel A, a pKa of 3.8 for lactic acid and a pKa of 4.76 for acetic acid. Filled symbols correspond to the samples taken during single-species cultivation while open symbols correspond to the samples taken during co-cultivation. The results presented are representative of, at least, three independent replicas.