Résumé
Production of alkaline protease by Bacillus licheniformis has been investigated under submerged fermentation. The physical and chemical parameters influencing submerged fermentation were optimized. The effect of incubation time, temperature, pH, carbon sources and nitrogen sources and additional nutrients on the production of alkaline protease was characterized. The optimum conditions for the protease production by Bacillus licheniformis were found to be at pH 9.0 and temperature at 40ºC. The outcome of carbon and inorganic nitrogen sources on protease production proved that glucose and casein were the effective medium ingredients for Bacillus licheniformis respectively. The maximum amount of protease production was recorded in medium supplemented with ammonium sulphate. Among the tested metal ions, the level of protease yield was found to be high in medium supplemented with magnesium chloride. The protease production was amplified in the presence of 1.5% sodium chloride. The extreme stability towards Triton X-100, Tween 20 and SDS was observed in Bacillus licheniformis alkaline protease.