Comparative effect of temperature on the oxidative metabolism of whole and disrupted cells of a psychrophilic and a mesophilic species of Bacillus.

We investigated the influence of temperature, in the range of 45 to 5 C, on the rate of oxidation of glucose and citrate by intact cells and cell-free extracts of psychrophilic Bacillus psychrophilus and mesophilic B. thuringiensis. Both glucose and endogenous oxidation by whole and disrupted cells of the psychrophile decreased more slowly with decrease in temperature than did glucose and endogenous oxidation by whole and disrupted cells of the mesophile. Similar results were obtained for the oxidation of citrate by cell-free extracts. Since substrate permeability is not involved in the oxidative metabolism of the cell-free extracts, we concluded that the internal enzymes of the psychrophile differ from those of the mesophile.