A novel highly active phosphatidylglycerol-phosphatidylinositol transfer protein (PG/PI-TP) was isolated from a cell-free extract of Aspergillus oryzae LMTC 2.14 grown on lecithin fractions as sole carbon source. A protocol for the extraction of the cytosolic PG/PI-TP that supports an extrapolation at industrial scale has been developed allowing the recovery of the active protein with high performance. Mycelium was harvested using a membrane press filter. A study of the cake permeability and compressibility which reflects the resistance of the cake to flow of liquid through pores was achieved in order to select the optimal working pressure (4 x 10(5) Pa). Mycelium disruption was achieved using a high-pressure homogenizer, with semi-continuous recycle. Two passes were necessary for an optimal recovery of PG/PI-TP. Removal of cell debris by filtration needed the use of 60 g 1(-1) Harbolite as filter aid. Tn the present growth conditions, mycelial intracellular lipid content was particularly high (approximate to 40% of the mycelial dry weight) leading to major problems during chromatographic steps. In order to remove lipids, the crude extract was treated with hexane. Under these conditions, the crude extract was significantly clarified without loss of PG/PI-TP activity. As molecular filtration is not a suitable first chromatographic step in industry. ion-exchange chromatography was performed as a pre-purification step. Under these conditions, a recovery of 52% active PG/PI-TP was obtained, i.e. an improvement of 3.47-fold compared with previous work at labscale level. (C) 2000 Elsevier Science Ltd. All rights reserved.