Physiological basis of CO(2) inhibition of a meat spoilage bacterium, Pseudomonas fluorescens.

CO(2) has been shown to have a number of effects on biological systems, but it is uncertain which of these are important in its inhibition of Gram-negative spoilage bacteria. The effects of CO(2) on intracellular pH, in vitro enzyme actities and substrate transport were examined to see if any changes in these functions could be correlated with the observed patterns of growth inhibition, which varied with the composition of the growth medium. CO(2) inhibition of growth could not be explained by postulating inhibition of intracellular enzymes, but inhibition of substrate uptake appears to correlate with-and offer a satisfactory explanation for-growth inhibition. However, the data do not allow the inhibition of substrate transport to be ascribed to a particular mode of action of CO(2).