Production de l'aspartyl protéase par pénicillium Camemberti cultive sur milieu à base de lactosérum

Abstract

The aspartyl-protease is produced by Pénicillium camemberti in fermentor of mulched aired to pH 4.0, under agitation to 240 rpm and temperture of 22°C. The middle is prepared from will. The daily withdrawals on a period of 15 days have permitted to establish die evolution of a microbial biomass in four plain phases. This one reaches its maximal value in dry weight (32g/ls) after 8 days of culture. An increase of the aspartyl proteasic activity is observed during the exponential phase; its value is reached after 10 days (1 078 US). This activity decreases slightly in end of fermentetion. Mathematicals models some kinetic profiles show that the production of the aspartyl protease is type partially associated to the growth of mildew. The out put in activitty reaches 64% after the precipitation and the dialysis. It is 50% after filtration on Sephadex Q75. The chromatogrphy on frost of Sephacryl S-200 gives a fraction of specific activity of 18 108 U/mgs. The purification permitted to draw profiles of elutions of proteins and aspartyl-proteasics activities and of to separate the enzyme with an output superior to 44% ant with a degree of purification of 30%. Enzymatic excerpt gotten present an optimal pH of 4.0, an optimal temperature of 40°C -45°C, a maximal stability situated in the interval of pH of 3.0 to 5.5, and aKm of 2,8 mg/mls.