Ultrafiltration (UF) membranes composed of biologically derived matrices, individually cross-linked onto ceramic microfilters using glutaraldehyde, cyanuric chloride and carbodiimide as fixing agents, are presented. The matrix was derived from a bovine aorta endothelial cell line. Their potential as industrial/scientific tools has been evaluated to include definitions of operational parameters such as flux rate (90-120 1/m(2) h), pressure (1-35 psi) and temperature (10-40 degrees C). Their stability upon exposure to different pHs, solvents, enzymes and sterilizing agents is also defined. The fouling nature and rejection properties of the matrix are examined and these suggest that the biological membrane compares very favourably with cellulose acetate UF membranes, currently among the market leaders in low fouling UF membranes.