Immobilization of Papain on the Mesoporous Molecular Sieve MCM‐48
ABSTRACT The immobilization of papain on the mesoporous molecular sieve MCM-48 (with a pore size of 6.2 nm in diameter) with the aid of glutaraldehyde, and the characteristics of this immobilized papain are described. The optimum conditions for immobilization were as follows: 20 mg native free enzyme/g of the MCM-48 and 0.75 % glutaraldehyde, 2 h at 10–20 °C and pH 7.0. Under these optimum conditions for immobilization, the activity yield [%] of the immobilized enzyme was around 70 %. The influence of the pH on the activity of the immobilized enzyme was much lower compared to the free enzyme. The thermostability of the immobilized enzyme, whose half-life was more than 2500 min, was greatly improved and was found to be significantly higher than that of the free enzyme (about 80 min). The immobilized enzyme also showed good operational stability, and the activity of the immobilized enzyme continued to maintain 76.5 % of the initial activity even after a 12-day continuous operation. Moreover, the immobilized enzyme still exhibited good storage stability. From these results, papain immobilized on the MCM-48 with the aid of glutaraldehyde, can be used as a high-performance biocatalyst in biotechnological processing, in particular in industrial and medical applications.
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ABSTRACT: The functionalized mesoporous activated carbon (FMAC) was used as support material for immobilization of acid protease (AP). Immobilization of acid protease on functionalized mesoporous activated carbon (AP–FMAC) performs as a suitable enzyme carrier. Under optimized condition pH (6.0) acid protease 150 mg g−1 FMAC has been adsorbed. The optimum temperature for both free and immobilized AP activities was 50 °C. After incubation at 50 °C, the immobilized AP maintained 50% of its initial activity, while the free enzyme was completely inactivated. A significant catalytic efficiency was maintained along for more than five consecutive reaction cycles in AP–FMAC combination immobilized system. The functional groups of the AP, FMAC and AP–FMAC were observed by Fourier transformer infrared spectroscopy (FT-IR). The scanning electron microscopy (SEM) allowed us to observe the morphology of the surface of FMAC and the AP–FMAC.Biochemical Engineering Journal 02/2009; 43(2-43):185-190. DOI:10.1016/j.bej.2008.09.017 · 2.37 Impact Factor
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ABSTRACT: The immobilization and electrochemistry of cytochrome c (cyt c) on amino-functionalized mesoporous silica thin films are described. The functionalized silica films with an Im3m cubic phase structure were deposited on conducting ITO substrate by co-condensation of tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES) in the presence of Pluronic F127 under acidic conditions. The high specific surface area, large pore size and functional inner surface of mesoporous silica thin films result in a high cyt c loading, and the cyt c immobilization on this silicate framework is stable. After adsorption of cyt c, the ordered cubic structure of mesoporous silica and the redox activity of immobilized cyt c are retained as demonstrated by X-ray diffraction (XRD), Transmission electron microscope (TEM) and cyclic voltammetry. The redox behavior of the cyt c/silica film-modified ITO electrode is a surface-controlled quasi-reversible process for the experimental conditions used in this work and the electron transfer rate constant is calculated is 1.33 s−1. The ITO electrode modified by cyt c/silica film possesses a high stability; even cyt c retains its redox activity following immobilization for several months. Furthermore, the electrocatalytic activities of the modified ITO electrode to hydrogen peroxide and ascorbic acid have been studied. Since these behaviors are quite pronounced, the modified electrode can be used for detection of hydrogen peroxide and ascorbic acid.Electrochemistry Communications 08/2007; 9(8-9):2098-2104. DOI:10.1016/j.elecom.2007.05.025 · 4.29 Impact Factor
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ABSTRACT: Complexation and interaction between silver and amino group were applied to induce an efficient immobilization of papain on silica spheres. The silver nanoparticles were deposited on the silica spheres before papain was coupled to the silica spheres. The silica spheres with silver nanoparticles were characterized by high resolution transmission electron microscopy (HR-TEM), Fournier transform infrared spectroscopy (FT-IR), and UV-Vis scanning spectrometer. FT-IR spectrum was also used to characterize the immobilized and free papain. Effect of some factors on the activities of the immobilized papain was investigated. It was observed that the coupled yield and relative activity of the papain on Ag/SiO2 were 1.17 and 1.86 times of those on the bare SiO2, respectively. At an optimum concentration of silver, the observed activity of the immobilized papain was 2.1 times of that on the bare silica. In addition, the maximum specific activity of papain immobilized on Ag/SiO2 was 819.9 U·mg−1, which is slightly lower than that of the free papain, 906.2 U·mg−1. Stability of the immobilized papain was also examined. The results indicate that the silver nanoparticles successfully induce a fine immobilization of papain.Chinese Journal of Chemical Engineering 01/2008; 16(4):612-619. DOI:10.1016/S1004-9541(08)60129-9 · 0.87 Impact Factor