The effect of carbon dioxide on bacterial growth and on uptake processes in bacterial membrane vesicles

The effect of different concentrations of carbon dioxide on growth rates of Escherichia coli, Bacillus sublitis, Bacillus cereus and Pseudomonas aeruginosa was studied by means of a microculture system. For B. subtilis and P. aeruginosa, growth rate was linearly inhibited up to a concentration of 40% carbon dioxide. For E. coli and B. cereus, the inhibition of growth rate followed non-linear curves (concave downwards) in the whole concentration range (5–80%). Uptake of amino acids in E. coli and B. subtilis membrane vesicles was inhibited only half as much as growth, and uptake of glucose in E. coli membrane vesicles was unaffected even by 100% carbon dioxide. These experiments seem to indicate that the main mechanism of action for carbon dioxide is not associated with physical disturbance of the bacterial membrane.