الفهرس | Only 14 pages are availabe for public view |
Abstract Silver nanoparticles (AgNPs) are being of major interest and being applied in various fields of nanotechnology. AgNPs synthesis can be obtained from endophytic fungi. In Egypt very few studies carried on the synthesis of AgNPs by endophytic fungi. Objective of current study involves the green synthesis optimization combined with photostimulation of silver nanoparticles from endophytic fungi of various medicinal plants species from South Sinai, Egypt. Survey of extracellular synthesis of AgNPs by endophytic fungi isolated from six wild medicinal plants in Wadi Al-Arbaein, Saint Katherine Protectorate, arid Sinai, Egypt were carried out. Twenty two entophytic species were isolated, 13 species of which were screened for AgNPs production. Out of 5 species were able to produce AgNPs, maximum AgNPs biosynthesis was obtained from two different endophytic fungi namely Trichoderma viride and Chaetomium globosum from the medicinally important plants Chiliadenus montanus and Tanacetum sinaicum respectively. Optimisation of AgNPs production by three different parameters was assessed in order to give the optimum condition for AgNPs biosynthesis, parameters were AgNO3 concentration, pH and temperature as these factors influence the activity of α-NADPH-dependent nitrate reductase enzyme that mediate the biosynthesis of AgNPs. Efficiency of photostimulation using monochromatic red polarized light and red light emitting diodes radiations on biosynthesis of AgNPs was also assessed. T. viride and Ch. globosum showed significantly different response to optimization conditions and photostimulation by either red polarized or red LED light. T. viride showed a promising results and significant increase in AgNPs production by temperature optimizing conditions and polarized light photo stimulation. Furthermore, biogenic and chemically synthetic AgNPs were compared in the term of the antimicrobial efficiency at different concentrations. Chemically reduced AgNPs showed only antibacterial activity, but endophytic fungi driven AgNPs showed broader spectrum antimicrobial effect against tested bacteria, yeast and fungal pathogens. Ultrastructure studies carried on AgNPs mediated by T. viride that possess the broader spectrum antimicrobial effect confirmed the presence of silver nanoparticles with a diameter in the range of 26.3-34.2 nm. Application of endophytic fungi of Egyptian medicinal plants in the field of bio-nanotechnology for green synthesis of broad spectrum, stable and safe antimicrobial AgNPs would be highly recommended. Abstract Chaetomium globosum, Trichoderma viride, green chemistry, Silver nanoparticles, Egyptian medicinal plants, Endophytic fungi. Key words II |