Table 1.

Intracellular pH measurements of selected Gram‐negative bacteria growing in LB medium

Bacterial strain	Relevant characteristics	Specific growth rate (h−1)	Cytoplasmic pH	Extracellular pH
E. coli DH5α	Laboratory strain typically used for cloning	1.46 ± 0.05	7.54 ± 0.11	6.05 ± 0.02
P. putida KT2440	Wild‐type strain, platform bacterial host	1.89 ± 0.06	7.77 ± 0.11	7.51 ± 0.01
P. aeruginosa PA14	Wild‐type strain, wide host virulence spectrum	0.92 ± 0.02	7.63 ± 0.08	7.12 ± 0.02
P. aeruginosa CH2682	Wild‐type strain, clinical isolate	0.57 ± 0.03	7.87 ± 0.07	7.54 ± 0.02

All strains, carrying plasmid pS2513·PHP, were grown in LB medium, and the cytoplasmic pH was determined during exponential growth. The pH of the LB medium was determined to be 7.05 ± 0.02 just prior to inoculation of the cultures. These results represent the mean value of each parameter ± standard deviation of triplicate measurements from at least three independent experiments.