| abstract |
Structures suitable for use as ultrafiltration membranes with membranes fixed to a support, and made of crystalline-arranged and intra- and intermolecular cross-linked protein molecules or protein-containing molecules, between which through-type pores remain open, with pore sizes of in particular 1 to 8 nm, whereby these molecules are obtained in particular from cell-envelopes of procaryots; the pore width is modified by changing the environmental conditions, such as the pH value, ionic strength or the ionic composition. The modifications serve in particular also to insert substances of value into the structures or to remove them therefrom. Structures of this type are also advantageously produced in this manner so that the substances of value can at the same time be inserted into the structure with the development of the latter. In order to produce such structures for use as ultrafiltering membranes, cell-wall fragments or cell envelopes are used which - in addition to the protein layers - can envelop the underlying cell support layers. Such structures are also suitable as separating deviices for gas separation or ion exchange, as a support structure for other semipermeable membranes, as well as separating material for chromatographic columns. |