الفهرس 
Literature ReviewOnly 14 pages are availabe for public view
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Abstract
With the development of new chemical or physical methods in nanoparticles production, the concern forenvironmental contaminations are also heightened as the chemical procedures involved in the synthesis ofnanomaterials generate a large amount of hazardous byproducts. Thus, there was a need for ‘green chemistry’ thatincludes a clean, nontoxic and environment-friendly method of nanoparticle synthesis.Thus, our study aimed to studying the biosynthesis of the silver nanoparticlesin different filamentous types of fungi.During our studydifferent filamentous fungi were isolated and identified then screened for silver nanoparticles biosynthesis. It was found that these filamentous fungi as (Aspergillusflavus, F.oxysporum, A. candidus, A. fumigatus, A. terrus, A.niger and P.citrinium) proved their ability for Ag-NPs biosynthesize via its metabolitesexudates.In addition, the study was planned toevaluate the difference between silver nanoparticles by the most potentA.flavus and its purified Peroxidase. Therefore, silvernanoparticles of different densities were investigated by different characterizing method that recorded absorbance at 436nm in case of A.flavus and 400nm at Peroxidase enzyme using UV-visible spectrophotometer. Zeta seizer measured the size of silver nanoparticles at (9 nm) for A. flavus and (80nm) for its Peroxidase one.TEM showed different shapes of silver nanoparticles such spherical, oval and triangle shapes without any aggregation in case of A.flavus. On the other hand, TEM reported homogenous spherical shape in case of purified Peroxidase with small aggregation. FTIR, proved the presence of amine and amide I,II and carbonyl bound at (1643.2 cm_1 (1), 1604.7cm_1 (2), 1801.4 cm_1, 3994.5 cm_1 and 3201.6 cm_1) in nanosilver by A.flavusas well as its negative charge showed higher stability beak at -30.3mv by zeta potential . Our results proved the best condition for purified Peroxidase with molecular weight at(140-160 kDa) on native gel and 70 kDa as optimum pH at 7.8. In addition T1/2 was 5.31h with thermal inactivation Kr at 70°C and Tm was 57.4for increasing its efficacy for silver nanoparticles biosynthesis. The purified Peroxidase was immobilized usingdifferent methods. characterization and kinetic studies for the potentimmobilized enzyme were conducted parallel to the free Peroixdase. The activity ofthe purified extracellular Peroxidase was 1.35fold higher than intracellular one from submerged cultures of A. flavus. Among the tested methods, polyacrylamide, Chitosanand Sod.alginatedisplayed the highest immobilizationefficiency. The thermal inactivation rate was strongly decreased for Sod-alginate , Polyacrylamide, chitosan and Sod.alginae Peroxidase (9x10-3, 8.64x 10-3 and s-1 8.5x 10-3 s-1) respectively comparing to free Peroxidase 4.6x10-2 s-1 at 700 c.Enzyme immobilization efficiency was greatly improved using of lysine and arginine as active site protectants. The activity of chitosan-Peroxidase wasincreased by 19.8% using arginine over its control. In addition, it wasincreased by 9.2% using lysine over its control. Results proved that the using of A. flavusto synthesize silver nanoparticles has a very slow process when in comparison with its purified enzyme. Hence, the use of purified Peroxidase to synthesize silver nanoparticles becomes an option that was feasible and its methods were fast and easy.Interestingly, silver naoparticles produced by A. flavus are more stable and remain for more time than the silver naoparticles produced by its purified Peroxidase. Thus, it was might be there are another bio-molecules beside these oxidoreductase enzyme inside fungal filtrate that shared in bio reduction of silver nitrite. In addition, our results proved the continuous production for silver nanoparticles by immobilized Peroxidase by Polyacrylamide and Sod.aliginate that achieved more stable than chitosan-Peroxidase.Thus, the continuous production for silver nanoparticles by immobilized Peroxidase by Polyacrylamide and Sod.aliginate was continuo for three months under controlled system In-addition, Polyacrylamide and Sod.aliginate Peroxidase gave stability till fifth cycle for production of silver nanoparticlescompared with free peroxidase that is produced for only one cycle. Also, that considered as new method in nanoparticles biosynthesis, in addition its purity, easy-ability, feasibility and stability of product compared with the biosynthesis by fungal biomass.