Among forty endophytic fungal isolates derived from the mangrove plant Avicennia marina, thirty-seven isolates (92.5 %) shown vary antimycotic activity against clinical Trichophyton, Microsporum, and Epidermophyton isolates. The hyperactive wild antagonistic strains Acremonium sp. MERV1 and Chaetomium sp. MERV7 were subjected to intergeneric protoplast fusion technique, and out of 20 fusants obtained, the fusant MERV6270 showed the highest antimycotic activity with the broadest spectrum against all dermatophytes under study. Solid-state fermentation (SSF) showed its superiority for antimycotic/antiviral metabolite production using cost-effective agroindustrial residues. Low-cost novel fermentation medium containing inexpensive substrate mixture of molokhia stalk, lemon peel, pomegranate peel, peanut peel (2:1:1:1) moistened with potato, and meat processing wastewaters (2:1, at moisture content of 60 %) provided a high antimycotic metabolite yield, 33.25 mg/gds, by the fusant MERV6270. The optimal parameters for antimycotic productivity under SSF were incubation period (4 days), incubation temperature (27.5-30 A degrees C), initial pH (6), initial moisture level (60 %), substrate particle size (1.0 mm), and inoculum size (2 x 10(6) spores/gds), which elucidated antimycotic activity to 44.19 mg/gds. Interestingly, wild mangrove Acremonium sp. MERV1 and Chaetomium sp. MERV7 strains and their fusant MERV6270 showed significant inhibition of hepatitis C virus with viral knockdown percent of -82.48, -82.44, and -97.37 %, respectively, compared to the control (100 %), which open a new era in combat epidemic viral diseases.