Antibacterial, Antifungal and Antibiofilm Activities of Silver Nanoparticles Supported by Crude Bioactive Metabolites of Bionanofactories Isolated from Lake Mariout

Abstract

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).

Biosynthesis of Silver Nanoparticles and Their Applications in Harvesting Sunlight for Solar Thermal Generation

“…Finally, the band at the 536 cm −1 region is most likely credited to C-Br stretching, which is typical of alkyl halides [93]. Other investigations reported that peaks at minor field in the range 400-700 cm −1 reflected the metallic nature of any examined sample, Ag NPs in our case [94]. As stated before, these functional groups, in general, have a role in the stability/capping of Ag NPs as reported in many studies [95][96][97][98].…”

Methyl Orange Biodegradation by Immobilized Consortium Microspheres: Experimental Design Approach, Toxicity Study and Bioaugmentation Potential

“…Such strains were isolated from different ecosystems that contained different pollutant loads. They exhibited characteristic biochemical and physiological capabilities and some of them were utilized previously in the bioremediation of heavy metals [ 58 ]. As noticed, the selected strains are affiliated to different bacterial classes encompassing alphaproteobacteria , gammaproteobacterial and firmicutes , which imply different behaviors in terms of the handling of substrates.…”

“…Dehydrated and lyophilized samples were triturated into fine powder, combined with KBr (1.0 percent w / w ) and crushed into transparent discs in a hydraulic press. Spectra were captured at 4 cm −1 resolution over a range of 4000–400 cm −1 with an accumulation of 64 scans and using dried air as a background [ 58 ].…”

One-pot fabrication of Ag @Ag2O core–shell nanostructures for biosafe antimicrobial and antibiofilm applications

“…Such fungal infections appeared recently in the second wave in India, in particular in patients who were put on mechanical ventilation in intensive—care units. The fungicidal property of Ag@Ag 2 ONCs could be assigned to the damage of the glycoprotein-glucan-chitin cross-linkage of fungi cell wall followed by sever alterations in cellular biochemistry 11 , 45 . In addition, it has been suggested that Ag nanoparticles interact with the proteins of the plasma membrane, which is responsible for keeping trans-membrane electrochemical potential gradient such as H + ATPase protein.…”