Urea production by the marine bacteria Delaya venusta and Pseudomonas stutzeri grown in a minimal medium

The present experiment showed that the marine bacteria Delaya venusta and Pseudomonas stutzeri produced urea when grown in a minimal medium without an external supply of organic nitrogen. The urea production rate depended on the bacterial state of growth, and the highest urea accumulation rates in the medium were found in the growth deceleration phase and in the beginning of the stationary phase. Urea did not accumulate in D. venusta cells, whereas the intracellular accumulation of urea in P. stutzeri cells exceeded urea accumulation in the medium during exponential growth. Further, D. venusta could, in contrast to P. stutzeri, hydrolyse urea. We suggest that intracellular purines and pyrimidines (in particular RNA) were potential sources for the observed urea production.