Naringinase induced from the fermented broth of marine-derived fungus Aspergillus niger was immobilized into grafted gel beads, to obtain biocatalytically active beads. The support for enzyme immobilization was characterized by ART-FTIR and TGA techniques. TGA revealed a significant improvement in the grafted gel’s thermal stability from 200 to 300 °C. Optimization of the enzyme loading capacity increased gradually by 28-fold from 32 U/g gel to 899 U/g gel beads, retaining 99 % of the enzyme immobilization efficiency and 88 % of the immobilization yield. The immobilization process highly improved the enzyme’s thermal stability from 50 to 70 °C, which is favored in food industries, and reusability test retained 100 % of the immobilized enzyme activity after 20 cycles. These results are very useful on the marketing and industrial levels.

This study describes the preparation of mucoadhesive alginate-chitosan beads containing theophylline intended for colon-specific delivery. The calcium alginate beads were coated with chitosan by the ionotropic hydrogelation method with a polyelectrolyte complex reaction between two oppositely charged polyions. The release profiles of theophylline from the beads were determined by ultraviolet-visible absorption measurement at 272 nm. Scanning electron microscopy was used for morphology observation. The in vitro mucoadhesive tests for particles were carried out with the freshly excised jejunum of Sprague-Dawley rats. The bead particles, which ranged in size from 200 to 400 lm, exhibited excellent mucoadhesive properties. The results showed that the formulated coated beads succeeded in controlling the release of theophylline over a 24-h period. In conclusion, the release of theophylline was found to be dependent on the composition of the beads, the component polymer and its possible interactions, and the bioadhesiveness.

The current demands of the world's biotechnological industries are enhancement in enzyme productivity and development of novel techniques for increasing their shelf life. Compared to free enzymes in solution, immobilized enzymes are more robust and more resistant to environmental changes. More importantly, the heterogeneity of the immobilized enzyme systems allows an easy recovery of both enzymes and products, multiple reuse of enzymes, continuous operation of enzymatic processes, rapid termination of reactions, and greater variety of bioreactor designs. This review summarizes immobilization definition, different immobilization methods, advantages and disadvantages of each method. In addition, it covers some food industries, protein purification, human nutrition, biodiesel production, and textile industry. In these industries, the use of enzymes has become an inevitable processing strategy when a perfect end product is desired. It also can be used in many other important industries including health care and pharmaceuticals applications. One of the best uses of enzymes in the modern life is their application in diagnose and treatment of many disease especially when used in drug delivery system or when used in nanoform.

SYNOPSISLinseed oil was epoxidized in situ with perbenzoic or peracetic acid to produce epoxidized linseed oil (I). Effect of type and concentration of the peracid and the reaction time on the characteristics of the produced epoxidized oil were studied. Various epoxidized polyurethanes (11) with different NCO/OH ratios as well as epoxidized polyesters (111) were prepared from (I). The results obtained for the evaluation of resins (11) and (

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Novel poly(glycidyl methacrylate)-grafted Nafion-phosphoric acid membranes for direct-oxidation methanol fuel cells were prepared with a potassium persulfate chemical initiation system for the first time. The introduced epoxy groups were converted to amine groups through a reaction with ethylenediamine, which consequently doped with phosphoric acid (APO 3 H) groups. The latter significantly contributed to enhancing the ionexchange capacity, mechanical properties, and thermal stability. Factors affecting the modification steps were studied. Changes in the chemical and morphological structure were verified through Fourier transform infrared spectroscopy, TGA, and scanning electron microscopy characterization. Various grafting percentages (GP%'s) up to 32.31% were obtained. As a result, the thickness of the grafted membranes increased. Furthermore, the methanol permeability of the modified membranes was reduced with increasing grafted polymer content compared with that of the Nafion membrane. An 83.64% reduction in the methanol permeability was obtained with a polymer grafted content of 18.27%. Finally, the efficiency factor for all of the modified Nafion membranes was enhanced compared with that of Nafion. A fourfold improvement was obtained with membranes with a GP% of 18.27% as a maximum value. Such promising results nominate the used technique as a one for the improvement of Nafion membrane efficiency.

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