Production des protéases par un isolat de Penicillium de l’eau de mer

Abstract

The marine environment prompts marine microorganisms to generate multiple enzyme systems to adapt to this complex environment. Therefore, marine microbial enzymes can offer new biocatalysts with extraordinary properties in the textile, leather, food and pharmaceutical industries and in various commercial detergent industries. In the present work, we carried out a quantitative and qualitative study of the fungi of three samples of sand from seawater taken from a beach of Sidi Medjdoub (Mostaganem). The results of fungi growth cultured in a PDA+3.5% NaCl and PDA+5% NaCl medium show the ability of these isolates of marine origin to tolerate these saline conditions The identification of the fungi achieved to four fungal genera (Penicillium, Cladosporium, a yeast and an isolate with sterile mycelium). Among these different isolates 1 fungi of the genus Penicillium was selected for it’s most proteolytic activity after screening on skimmed milk agar. This selected isolate was inoculated into a production medium in an Erlenmeyer flask incubated for 72 hours with shaking. The crude enzyme was obtained after filtration and centrifugation. The determination of the proteolytic activity of this enzyme was carried out by the method of diffusion of agar wells on skimmed milk agar where the diameter of the lysis zone reached 50 mm.