Figure 6.

In combination with pH at or below 6, acetic, butyric, and propionic acid impair growth significantly more strongly than the other acids regardless of strain background. (A) Heat map of mean carrying capacity estimates from the phenom model. In each heat map subpanel, OA concentrations are shown on the X-axis and pH levels on the Y-axis. In the heat map grid, PAO1 strain is given in the left column and PA1054 in the right. OA type is given in the rows. Brighter cyan intensity indicates a lower carrying capacity (see color legend at far right). (B) Bar graph rank ordering OA types in terms of mean carrying capacity across strains. OA types with the greatest bacteriostatic effect are shown at top, the weakest on the bottom. (C) Heat map of the mean effect on carrying capacity for highly active OA types (propionic, butyric, acetic), vs. weakly active (citric, sorbic, malic, benzoic). Carrying capacities were averaged across acids in each category at each pH and across strains. (D) Density histogram of carrying capacities for highly active OAs (cyan) vs. weakly active OAs (gray) at growth limiting concentrations. Each tick in the rug plot beneath the histograms represents an individual carrying capacity value at a given pH/OA combination in a given strain. (E) Density histograms of carrying capacities for cultures of PAO1 and PA1054 at concentrations of OA and pH levels that allow for growth. Ticks in rug plot represent individual carrying capacity values. (F) Density histograms of carrying capacities for cultures of PAO1 (black) and PA1054 (magenta) at growth limiting concentrations. Ticks in rug plot represent individual carrying capacity values.