Nutritional studies with Pseudomonas aeruginosa grown on inorganic sulfur sources

Pseudomonas aeruginosa was grown on a succinate-basal salts medium supplemented with various inorganic sulfur compounds as its sole source of sulfur. The organism was able to grow on the sodium salts of sulfide, thiosulfate, tetrathionate, dithionite, metabisulfite, sulfite, or sulfate, but not on those of dithionate. Analyses of the culture media after 24 h of growth indicated accumulation of sulfate from each inorganic sulfur source except sulfate. Manometric studies with resting cells obtained by growth on each of these sulfur sources yielded net oxygen uptake for all substrates except sulfite and dithionate. Similar results were obtained with extracts from these cells by spectrophotometric techniques. Thiosulfate oxidase activity appeared to be induced by growth on sulfide, thiosulfate, or tetrathionate, with little or no activity observed when cells were grown on inorganic sulfur sources of higher oxidative states. Metabisulfite oxidase appeared to be associated with growth on all inorganic sulfur compounds. Rhodanese activity appeared to be constitutively present, and its activity, observed only in soluble fraction, seemed independent of the growth medium employed. Thiosulfate and tetrathionate oxidase activities were studied in greater detail than some of the other sulfur oxidases, and both were found to be distributed between particulate and soluble fractions.