Figure 1. Main statistical contrasts on viable cell concentration in midexponential phase (X_me), viable cell concentration in stationary phase (X_s), viability in midexponential phase (V_me) and cell growth rate (µ) determined through the 2^5-1 fractional factorial design for glucose, yeast extract (YE), Pluronic F68 (PF68), fetal bovine serum (FBS) and milk whey retentate (MWR). Cells were inoculated in different media at a final concentration of 2.5 x 10⁵ cells.ml^-1 and cultivated at 28ºC.