Antibodies were raised against purified xylanase from Thermomyces lanuginosus SSBP in mice. The anti-xylanase antibody had a 1092 dilution of four at day 39 as determined using enzyme-linked immunosorbent assay. The xylanase enzyme was adsorbed onto polysulphone membranes and the primary antibody was attached. An immunogold labelled secondary anti-mouse antibody was attached to the primary antibody to locate the enzyme on the membrane. Using an environmental scanning electron microscope, inimunogold labelled xylanase was visible at 50000 x magnification on the surface and the pores of the membrane. Controls showed no sign of immunogold particles. (C) 2002 Elsevier Science Ltd. All rights reserved.