Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute (GEBRI), City of Scientific Research and Technological Applications (SRTA-City), New Borg El-Arab City 21934, Alexandria, Egypt.
Department of Biology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.
Molecules. 2021 May 19;26(10):3027. doi: 10.3390/molecules26103027.
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 strains were screened, from Lake Mariout's sediment for bioreduction of 5 mM AgNO. 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).
马里奥特湖是埃及受污染的沿海海洋生态系统之一，被认为是各种人为活动严重废水的蓄水池。这种选择性压力迫使本土微生物种群获得新的有利主题。因此，在这项研究中，从马里奥特湖的沉积物中筛选出了两株能够将 5mM AgNO 还原的菌株。这两株菌都通过分子鉴定进行了鉴定；它们的生化和生理特性表明它们能够分泌具有拮抗活性的生物活性代谢物。评估了影响 AgNPs 生产力的培养和孵化条件。随后，研究了生物制造的 AgNPs 的物理化学性质。紫外可见光谱在 458-422nm 范围内检测到表面等离子体共振。XRD 表明 AgNPs 为结晶、纯、面心立方；EDX 在 3.5keV 处显示出强烈的银信号。此外，FT-IR 和 TGA 分析表明 AgNPs 由生物有机分子自稳定和功能化。然而，电子显微镜照片显示出许多均匀的球形 AgNPs（1.17-13.3nm）。抑菌圈抑制试验在 50μg/mL 时记录到了强大的杀菌和杀真菌活性。此外，生物膜活性呈剂量依赖性。此外，AgNPs 与两个生物纳米工厂的粗生物活性代谢物的结合提高了抗菌效力，反映出对测试病原体（自由生活和生物膜）的协同效率。
