Studies on the Production of Extracellular Proteinases by a Non‐pigmented Strain of Chromobacterium lividum Isolated from Abattoir Effluent

A highly proteolytic bacterium isolated from abattoir effluent was identified as a non‐pigmented strain of Chromobacterium lividum. Ferrous or ferric ions at concentrations between 1·8 × 10 ‐5 and 9 × 10 ‐4 g ions/1, which is 2–3 orders of magnitude greater than that required for growth, were essential for extracellular proteinase production in aerated but not in static culture. Co 2+ , Ni 2+ , Mn 2+ , Cu 2+ or Zn 2+ ions could not replace iron. Four proteinases (I‐IV) were produced in static culture, but only proteinase I was formed in significant quantities in aerated culture. With both forms of culture amino nitrogen was essential for proteinase production; glucose inhibited formation in aerated, but not static, cultures. Growth occurred over the range 1–33 °C, whereas proteinase production ceased at 27 °C, with maximum activity at 13 °C. Proteinase production appeared to be controlled by an interaction between iron, oxygen tension and glucose.