This study aimed to test the protein hydro lysate prepared by enzymic treatment of Siluris glanis viscera with serine proteases in microorganism's growth. The processing methods included four treatments, namely T1, T2 fish samples were digested with 0.2M acetate buffer and pH 4.5 at 6 and 12 hours, and T3, and T4 were digested using the crude extract of serine protease 120 unitml and pH 6.5, 0.2M at 6 and 12 hours, respectively. The undigested residues were removed by centrifugation, the clarified digests were pasteurized at 80c°10min, cooled, and the solidified fat layer removed then pH was adjusted to 6.5. The obtained hydro lysate was dried under vacuum at 50c°, and four samples were obtained and designated as P1, P2, P3 and P4.
The percentages of moisture, ash, fat and protein were for P1 6, 1.10, 0.40, 92.5%, respectively, and for P2 6.2, 1.45, 0.45 and 91.9 %, also, P3 5.4, 1.62, 0.48, 92.5% and P4 were 5.3, 1.70, 0.5, 92,5%, respectively. The percentages of peptone nitrogen, total protease nitrogen, secondary protease nitrogen , primary protease nitrogen and amino acid nitrogen were 3.1, 1.95, 0.30, 1.65 and 0.4% respectively for P1,also, 4.5, 3.01, 0.36, 2.65 and 0.6 % for P2, in addition, 5.1, 2.5, 0.37, 2.13 and 0.65 % for P3, for P4 7.3, 3.5, 0.40, 3.1 and 0.8%. The above hydro lysate were applied to some growth media such as MRS that prepared for Lactobacillus acidophilus, Davis´s Yeast Salt that prepared for Kluyveormyces marxianus and Potato Dextrose Agar that prepared for Aspergillus nigir. The results showed that hydro lysates contained media were more effective in promoting the growth of the experimental organisms as compared with that of standard media.