SUMMARY: The effect of medium composition on the production of four types of extracellular enzymes by was investigated. The nuclease, RNAase, alkaline phosphatase and proteases were produced in good yield after growth in tryptone broth. Much higher yields of the proteases, but low yields of the other three enzymes, were obtained using a skim milk/yeast extract or a chemically defined medium. The addition of NH , HPO , ribonucleosides, Mg or Mn to tryptone broth reduced the production of some of the enzymes rather specifically. Of 12 monovalent and divalent metal ions tested, Mg and Mn had the greatest effect. Mg at concentrations greater than about 0.01 mM inhibited the production of the nuclease, RNAase and the phosphatase but increased the proteases two- to threefold. Mn at concentrations greater than about 0.01 mM inhibited production of the three enzymes more severely but did not stimulate protease synthesis. The extracellular enzymes produced with or without added Mg or Mn were analysed by PAGE and the activities associated with the cells and a shock fluid were determined. In addition, the effect of adding Mg or Mn to a growing, extracellular enzyme-producing culture was determined. The results suggest that the nuclease, RNAase and phosphatase are produced by a different mechanism than the proteases and that the metal ions interfere specifically with their production rather than with their release or by causing inhibition.


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