Optimum Lipase Immobilized on Diamine-Grafted PVDF Membrane and Its Characterization

A facile and economic modification of polyvinylidene fluoride (PVDF) with an orientation of diamine is presented herein. The physical characterizations of native and diamine-grafted PVDF membranes are analyzed by three different techniques: the ninhydrin test, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The diamine-grafted PVDF is activated by glutaraldehyde for enzyme immobilization. The response surface methodology (RSM) is used to search the optimal immobilization conditions and to understand the significance of the factors affecting the responses of immobilized lipase. The optimal conditions for lipase immobilization are: a reaction time of 90 min, temperature of 35 degrees C, pH of 6, and an enzyme concentration of 7 mg/mL. An experiment performed under the optimum conditions obtains lipase activity of 60 U per g of membrane. A good agreement between the calculated and experimental values is thereby achieved

Optimal covalent immobilization of alpha-chymotrypsin on Fe3O4-chitosan nanoparticles

This study investigated the immobilization of alpha-chymotrypsin onto magnetic Fe3O4-chitosan (alpha-chymotrypsin-Fe3O4-CS) nanoparticles by covalent binding. The response surface methodology (RSM) with a 3-factor-3-level Box-Behnken experimental design was employed to evaluate the effects of the manipulated variables, including the immobilization time, temperature, and pH, on the enzyme activity. The results indicate that the immobilized temperature and pH significantly affected enzyme activity. In a ridge max analysis, the optimal condition for alpha-chymotrypsin immobilization included a reaction temperature of 21.7 degrees C, a pH of 7.6, and an incubation time of 1.1 h. The predicted and the experimental immobilized enzyme activities were 354 and 347 +/- 46.5 U/g-support, respectively, under the optimal condition. Besides, the synthesis reactions of the dipeptide derivative using the free and immobilized alpha-chymotrypsin were compared. The yields of the dipepticle derivative via the free or immobilized alpha-chymotrypsin catalyzed were almost the same. The alpha-chymotrypsin-Fe3O4-CS nanoparticles exhibited a good acid-resisting ability and the less reaction time was required for dipeptide synthesis. After twelve repeated uses in dipeptide synthesis, the immobilized alpha-chymotrypsin still retained over 60% of its original activity. The magnetic alpha-chymotrypsin-Fe3O4-CS nanoparticles can be easily recovered by magnetic field will have potential application in industry. (C) 2012 Elsevier By. All rights reserved

Oestrogen-induced epithelial-mesenchymal transition of endometrial epithelial cells contributes to the development of adenomyosis

Adenomyosis is an oestrogen-dependent disease caused by a downward extension of the endometrium into the uterine myometrium. Epithelial-mesenchymal transition (EMT) endows cells with migratory and invasive properties and can be induced by oestrogen. We hypothesized that oestrogen-induced EMT is critical in the pathogenesis of adenomyosis. We first investigated whether EMT occurred in adenomyotic lesions and whether it correlated with serum 17 beta-oestradiol (E2) levels. Immunohistochemistry was performed on adenomyotic lesions and corresponding eutopic endometrium samples from women with adenomyosis. Endometria from women without endometrial disorders were used as a control. In the epithelial component of adenomyotic lesions, vimentin expression was up-regulated and E-cadherin expression was down-regulated compared to the eutopic endometrium, suggesting that EMT occurs in adenomyosis. In adenomyosis, the serum E2 level was negatively correlated with E-cadherin expression in the epithelial components of the eutopic endometrium and adenomyotic lesions, suggesting the involvement of oestrogen-induced EMT in endometrial cells. In oestrogen receptor-positive Ishikawa endometrial epithelial cells, oestrogen induced a morphological change to a fibroblast-like phenotype, a shift from epithelial marker expression to mesenchymal marker expression, increased migration and invasion, and up-regulation of the EMT regulator Slug. Raloxifene, a selective oestrogen receptor modulator, abrogated these effects. To determine the role of oestrogen-induced EMT in the implantation of ectopic endometrium, we xenotransplanted eutopic endometrium or adenomyotic lesions from adenomyosis patients into ovariectomized SCID mice. The implantation of endometrium was oestrogen-dependent and was suppressed by raloxifene. Collectively, these data highlight the crucial role of oestrogen-induced EMT in the development of adenomyosis and suggest that raloxifene may be a potential therapeutic agent for adenomyosis patients. (C) Copyright 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd

A continuous ultrasound-assisted packed-bed bioreactor for the lipase-catalyzed synthesis of caffeic acid phenethyl ester

BACKGROUND: The focus of this paper is the ultrasound-assisted synthesis of caffeic acid phenethyl ester (CAPE) from caffeic acid and phenyl ethanol in a continuous packed-bed bioreactor. Immobilized Novozym (R) 435 (from Candida antarctica) is used as the catalyst. A three-level-three-factor Box-Behnken design and a response surface methodology (RSM) are employed to evaluate the effects of temperature, flow rate, and ultrasonic power on the percentage molar conversion of CAPE. RESULTS: Based on ridge max analysis, it is concluded that the optimum condition for synthesis is reaction temperature 72.66 degrees C, flow rate 0.046 mL min(-1), and ultrasonic power 1.64 W cm(-2). The expected molar conversion value is 97.84%. An experiment performed under these optimal conditions resulted in a molar conversion of 92.11 +/- 0.75%. The enzyme in the bioreactor was found to be stable for at least 6 days. CONCLUSIONS: The lipase-catalyzed synthesis of CAPE by an ultrasound-assisted packed-bed bioreactor uses mild reaction conditions. Enzymatic synthesis of CAPE is suitable for use in the nutraceutical and food production industries. (C) 2011 Society of Chemical Industr