In the design of a membrane bioreactor, the membrane morphology is a very important aspect, as the membrane should be developed or chosen to provide maximum surface area and an ideal environment for biofilm development. An investigation was carried out to identify membranes suitable for spore immobilisation, biofilm development and extracellular enzyme production from Phanerochaete chrysosporium. An internally skinned capillary polysulphone, two tubular aluminium oxide ceramic membranes with an average pore size of 0.2 and 3 mu m respectively and one capillary titanium oxide ceramic membrane with an average pore size of 3 mu m were identified and tested. The highest attachment and immobilisation of spores were observed on the capillary membranes with less on the tubular ceramic membranes. On average biofilm thicknesses of 1140 mu m were developed on the 3 mu m capillary ceramic membrane, 830 mu m on the capillary polysulphone membrane, 400 mu m on the 3 mu m tubular ceramic membrane with only 40 mu m on the 0.2 mu m tubular ceramic membrane. Continuous LiP and MnP enzyme production was achieved with both the polysulphone and capillary ceramic membrane reactors and no activity was detected with the tubular ceramic membrane reactors. However, for day-to-day operation of the reactor, the ceramic membranes were more rigid, mechanically stable and could be chemically and steam cleaned for re-use. (c) 2005 Elsevier B.V. All rights reserved.