الفهرس 
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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
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