The optimum temperature for growth of and extracellular proteinase production by Micrococcus GF was ses 30 oC. Growth was more rapid and proteoly1ic activity was enhanced by aeration. The microorganism grew and was able to produce extracellular proteinase on casaminoacids, gelatin, phytone peptone, glutamic acid and glutamine, but not on the other amino acids as the sole carbon/nitrogen source. Proteolytic activity decreased after the early exponential phase when Micrococcus GF was grown either

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... on 1% casaminoacids or 1% gelatin, but not wh en grown on casarnlnoacids plus gelatin or phytone peptone. NH 4 CI had an inhibitory effect on growth rate, but it affected neither the proteoly1ic activity nor the final bacterial count when the microorganism grew on organic N plus NH 4 CI. When Micrococcus GF was grown at different phytone peptone concentrations, the shortest generation time was observed with 2% phytone peptone; proteoly1ic activity was constant in the range 1-2% phytone peptone. Glucose and maltose did not affect proteinase production, but the gene~ation time was increased by <': 1% glucose. Maltose had a slight inhibitory effect on growth as weill as on proteinase production. Addition of NaCI to the culture medium supressed proteinase production by Micrococcus GF. The shortest generation time was observed in 2% NaCI, and the microorganism was able to grow in phytone peptone broth (2%) containing 12%, but not 14% NaCI. En faisant varier la concentration en peptone phytone, le temps de génération de Micrococcus était le plus court avec une concentration de 2%. L'activité protéolytique était constante avec la peptone phytone de 1 à 2%. Le glucose et le maltose n'affectent pas la production de protéinase. Cependant quand la concentration de glucose était supérieure à 1%, le temps de génération augmentait et le maltose avait un léger effet inhibiteur aussi bien sur la croissance que sur la production de protéinase. L'addition de NaCI au milieu de culture réprime la production de protéinase par Microccocus GF. Le temps de génération le plus court était observé avec NaCI 2% et le microorganisme était capable de croïtre dans un bouillon de peptone phytone (2%) contenant NaC112% (et non NaCI14%).