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Chitosan-silica (CSSi) hybrid films have been fabricated by sol-gel process using tetraethoxysilane (TEOS) as precursor. The structure of the resulting hybrid has been characterized by Fourier transform infrared spectroscopy (FTIR). Fracture surface has been revealed through a field emission-scanning electron microscopy/energy dispersive spectrometer (FE-SEM/EDS) to probe the dispersion degree and the size ofSiO2particle. Study of morphology using a SEM micrograph and the High Resolution Transmission Electron Microscopy (HRTEM) images of the nanocomposite films suggests that theSiO2nanoparticles are within the range of 2–7 nm in diameter and are uniformly dispersed in the polymer matrix. Thermal properties of these composite materials have been studied as a function of silica, indicating that thermal stability of the chitosan film is enhanced. Dynamical mechanical thermal analysis (DMTA) has been carried out to measure the shift in the glass transition temperature (Tg) of the composites from the maxima of theαtransition curves. The glass transition temperature and the storage modulus show an increase with increasing silica content. The maximum increase in theTgvalue, that is,159.37∘C,is seen with 30 wt% silica. A gradual increase of 3.0 GPa in the modulus relative to the pure polymer is observed.

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Tannase has great commercial significance in the feed, drink and medical industries, tannase is an enzyme catalyzing the hydrolysis ofthe ester bonds of tannic acid, a water soluble polyphenol secondary metabolites that present in many different parts of plants, to produce gallic acid and glucose and galloyl esters. Although several substrates for the production of tannase have been reported as being economically effective such as utilization of tanninrich substrate rather than pure tannic acid, however, there is still need to develop the substrate to make the entire process much cheaper and more effective. Here we reported tannase production from Erwinia as there is not found any report on tannase production from Erwinia. The present work deals with physiological studies on bacterial tannase. Out of 50 spoilt cucumber and tomato samples from local markets in Baghdad city. Eleven isolates from Erwiniacarotovora were obtained (22%). Tannase activity was found in 7 isolates in primary and secondary screening and the isolate ErwiniacarotovoraEt 3 yielded the highest tannase production. The enzyme activity was increased to 62.6 U/ml when this isolate was cultivated under the optimal conditions which consisted of using basal medium containing(5% w/v) pomegranate peels extract and (2% w/v)ammonium nitrate with pH 5.0 at 30°C for 24 hour. The metal ions K + , Ca ++ , Na + , Mg ++ and Mn ++ did not affect enzyme production. However, metal ions like Zn ++ , Cu ++ , Co ++ , Fe +++ and detergents inhibited the production of tannase. The enzyme revealed maximum activity (79.50U/ml) with pomegranate peels powder(1% w/v), followed by eucalyptus and pine barks powders with relative activities of 127,112 and 103%, respectively, as substrates. Consequently, pomegranate peel has a potential as an effective and much cheaper (economical) substrate for tannase production and tannase activity in comparison with traditionally used substrates like tannic acid and other saccharides.