Seven morphologically distinct marine fungi were isolated from sediment and Seawater samples at different sites along Alexandria seashore. Antagonism effect against Aeromonas hydrophila on purpose and other pathogen was estimated. The most promising isolate giving the highest antibacterial activity (14 mm) against A. hydrophila was morphologically and genetically identified as Aspergillus terreus SHE05 and the corresponding sequence was recorded in the GenBank database with accession no. MW772239. Time course production of the antibacterial agents by A. terreus SHE05 against A. hydrophila was studied showing the highest productivity after 5 days incubation. Multi-factorial design in terms of Placket Burman design was implemented to predict the critical factors influencing the production of the antibacterial agents by A. terreus SHE05 against A. hydrophila. The obtained results showed that malt extract, pH and temperature were the key factors affecting the antimicrobial activity. Consequently, Box-Behnken design was applied to estimate the optimized levels of each independent variable showing that the optimized conditions were malt extract, 3 (g/l); peptone, 0.75 (g/l); salinity, 50%; pH, 4; culture age, 4 days; inoculum size, 0.5 ml; temperature 30°C and incubation time 5 days, which caused an increase in the antimicrobial activity to 25 mm, which denotes an approximately 1.8 fold increase comparing with the pre-optimized conditions. The potentiality of chloroform, hexane, petroleum ether and ethyl acetate for extraction of the active compounds was tested showing that ethyl acetate was the best. The extracted bioactive metabolites using ethyl acetate were tested as antimicrobial, anticancer, antiviral and antioxidant agents. Results showed reasonable activities. GC-MS was used to recognize the active components in the ethyl acetate extract, showing that the major compound was the Dodecanamine, N,N-Dimethyl with RT 11.95, molecular weight 213, area % (55.46) and molecular formula C14H31N.
Fungi, optimization, response surface methodology, antimicrobial, anticancer, antiviral, antioxidant
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