Lake Mariout is one of the polluted coastal marine ecosystems in Egypt which is considered to be a reservoir of serious effluents from different anthropogenic activities. Such selective pressure enforces indigenous microbial populations to acquire new advantageous themes. Thus, in this study, two Streptomyces strains were screened, from Lake Mariout’s sediment for bioreduction of 5 mM AgNO3. Both strains were identified molecularly; their biochemical and physiological characterization revealed their ability to secrete bioactive metabolites with antagonistic activity. The cultural and incubation conditions influencing AgNPs productivity were evaluated. Subsequently, the physicochemical properties of the biofabricated AgNPs were pursued. UV-Vis spectroscopy detected surface plasmon resonance at range 458–422 nm. XRD indicated crystalline, pure, face-centered cubic AgNPs; EDX demonstrated strong silver signal at 3.5 keV. Besides, FT-IR and TGA analysis unveiled self-stabilization and functionalization of AgNPs by bioorganic molecules. However, electron microscopy micrographs depicted numerous uniform spherical AgNPs (1.17–13.3 nm). Potent bactericidal and fungicide activity were recorded by zone of inhibition assay at 50 μg/mL. Further, the antibiofilm activity was exerted in a dose-dependent manner. Moreover, the conjugation of AgNPs with the crude bioactive metabolites of both bionanofactories ameliorated the antimicrobial potency, reflecting a synergistic efficiency versus examined pathogens (free-living and biofilm).

Few species of filamentous fungi can accumulate considerable amounts of intracellular lipids when grown under certain stress conditions; thus, they can be used for biodiesel production. Moreover, their residual biomass can be used for the removal of heavy metals from contaminated water. An oleaginous Aspergillus fumigatus GAH1 isolate was isolated from a soil sample in Borg El-Arab industrial area, Alexandria, Egypt, and was characterized in batch cultures. The influence of different carbon and nitrogen sources and the initial pH of the medium on the fungal biomass and lipid production was investigated. Under optimized conditions, the A. fumigatus GAH1 isolate could accumulate up to 22.4% of its dry biomass as lipids. Oleic and palmitic acids were the dominant fatty acid fractions produced. After lipid extraction, to further improve the process economy, the fungal biomass was applied as a biosorbent to remove heavy metals such as Cr, Cd, and Zn from contaminated wastewater. The biosorption efficiency and capacity of the raw, H 2 O-washed, and NaOH-treated fungal biomass were examined. The biosorption capacity of 33.37, 29.29, and 27.75 mg/g was recorded for Cr, Cd, and Zn, respectively. Moreover, the biosorption efficiency was more than 69% for the tested heavy metals. In conclusion, A. fumigatus GAH1 may be considered as a promising biodiesel producer, and its biomass waste can be further used for the biosorption of heavy metals from contaminated wastewater.