Homogenization French press

To reduee vesiele size and the number of bilayers, high pressure filtration via polyearbonate membranes as well as high pressure homogenization in a French press or in a mierofiuidizer are appropriate manufacturing procedures. Sonieation may also be applied, although the resulting dispersion does not have the same particle sizes. 

Mechanical disruption methods include sonica-tion, high-speed homogenization using a French press, and bead milling, which is especially suitable... 

In a simple model of homogenization in a French press, the process of the disruption of the cell wall is modeled by a first-order law. Then, the amount of protein released, R, varies with the number of passes of broth through the homogenizer, N [Eq. (8.58)], where Rm3X is the maximum amount of protein obtainable through homogenization and k is a constant. 

Ball mills are best suited for breaking up strong cell walls such as those encountered in Gram-positive bacteria, but scale-up is limited beyond the small pilot scale. French presses are the apparatus of choice for large-scale homogenization of cells. 

For enzyme purification, 10 g (wet weight) of cells is freeze-thawed and resuspended in 40 ml of 20 roM Tris buffer, pH 8.4,2 mAf EDTA, 1M NaCl, and homogenized in a French press for 20 min. The homogenate is centrifuged at 160,000g for 90 min at 4° the supernatant (30 ml) represents the crude extract, and this catalyzes the reduction of insulin in the presence of DTT at 30° as described below. 

Anabaena variabilis, ATCC 29413, were grown at 302 C in continuous fluorescence light and collected in late log phase at room temperature. Thylakoid membranes were obtained by chilled french press treatment at 12000 psi in HEPES buffer (pH=7.5), with sorbitol 0.2 M and MgC12 10 mM. The homogenate was centrifugated at 2000 x g... 

Break down cells by applying a French press device nntil homogeneity see Note 9). 

LA CIN TIQUE CHIMIQUE HOMOGENE First published by Presses Universitaires de France, Paris, 1971 Translated from the French by J. T. Edward... 

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