A rapid way of synthesizing silver nanoparticles (AgNPs) by treating Ag+ ions with a green Fortunella Japonica (F.J.) extract as a combined reducing and stabilizing agent was investigated. The reaction solutions were monitored using UV-Vis spectroscopy, the size and shape of crystals were determined by scanning electron microscopy and transmission electron microscopy, the crystalline phases of AgNPs were presented by X–ray diffraction, and the relation of nanoparticles with Fortunella Japonica extract was confirmed using fourier transform infrared spectroscopy. The results indicated that no formation of AgNPs had taken place in the dark during 24 hours at room temperature and 40 oC. Meanwhile, it was found that the rate of AgNPs formation increased rapidly under the sunlight. The effects of the synthesis factors on the AgNPs formation were investigated. The suitable conditions for the synthesis of AgNPs using F.J. extract were determined as follows: F.J. extract was mixed with AgNO3 1.75 mM solution with the volume ratio of 3.5 AgNO3 solution/1.5 F.J. Extract, stirred 300 rpm for 150 minutes at 40 oC under sunlight illumination. At these conditions, AgNPs showed high crystalline structure with the average size of 15.9 nm. The antibacterial activity of silver nanoparticles was determined by agar well diffusion method against E. coli and B. subtilis bacteria. The green synthesized AgNPs performed high antibacterial activity against both bacteria.

Silver nanoparticles (AgNPs) were synthesized from aqueous AgNO 3 precursor via an effective and ecofriendly method using Lemon Citrus Latifolia (LCL) extract as the reducing and stabilizing agent under sunlight condition. The AgNPs formation was confirmed by ultraviolet-visible absorption spectroscopy at the wavelength of 400450 nm. The appropriate conditions and positive effect of direct sunlight on the AgNPs preparation were revealed clearly. The synthesized AgNPs were characterized using multitechniques X-ray diffraction revealed that AgNPs had the crystalline nature of face-centered cubic structure. Scanning electron microscopy and transmission electron microscopy showed the obtained AgNPs was spherical and the size distribution was uniform with the nanosize of 424 nm. The obtained AgNPs solution showed an effective antibacterial activity against E. coli, B. subtilis and B. cereus with the average diameter of inhibition zones over 15 mm.

mHT(Zn) and mHT(Mg) hydrotalcites were fabricated by coprecipitation of Zn 2+ /Al 3+ and Mg 2+ /Al 3+ salt mixtures in the presence of Fe3O4 and used as supports for immobilizing cellulase to form cell@mHT(Zn) and cell@mHT(Mg). The structure and properties of mHT(Zn), mHT(Mg), cell@mHT(Zn), and cell@mHT(Mg) were characterized by Fourier−transform infrared spectroscopy, X-ray diffraction, filtering electron microscopy. The effect of pH, cellulase concentration, and the number of supports on the immobilization of cellulase onto supports were carefully investigated. The enzyme activity of free cellulase, immobilized cellulase, and immobilization efficiency was analyzed by determining reduced glucose using DNS as a color indicator. The highest immobilization efficiency obtained was 94.9 % when carried out on mHT(Zn) at pH 6.5 and 95.3 % on mHT(Mg) and the concentration of cellulase in 0.1mg/mL at the pH of 5.5, using 0.2 g of supports. Cell@mHT(Zn) and cell@mHT(Mg) show high enzyme activity when reacting with 1 % CMC solution at 50 o C with relative enzyme activity of 78.0% and 70.4 %, respectively.

Magnetic ZnAl hydrotalcite (mHT) was synthesized by co-precipitation of Zn 2+ /Al 3+ salt mixture in the presence of Fe 3 O 4 . mHT nanomaterials were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, vibrating-sample magnetometer, and nitrogen adsorption isotherm. Then, mHT was used as support for immobilizing cellulase under an adsorption mechanism to form cell@mHT. The effect of pH, cellulase concentration, the amount of mHT, and immobilization time on the immobilization of cellulase onto mHT were carefully investigated. The enzyme activity of both free cellulase and cell@mHT as well as immobilization efficiency, was analyzed by determination of reduced glucose using DNS as a color indicator. The immobilization process obtained the highest loading efficiency with 99.0% when carried out at pH 5, with a cellulase concentration of 0.1 mg/ml and using 0.1 g of mHT. Cell@mHT shows good enzyme activity when reacting with 1 mass% CMC solution at 50°C after 45 minutes with relative enzyme activity of 80.8%.