The effective production and secretion of chitosanase from S. griseus cells, in the presence of hydrogen peroxide, were studied by the treatment of the cells with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) liposomes under heat condition. The variation of the conformation and activity of the chitosanase caused by the interaction of liposomes with target chitosanase under stress condition was systematically investigated by using circular dichroism (CD) spectra and dielectric dispersion analysis (DDA). The effect of the oxidative stress (hydrogen peroxide) on the lipid and protein peroxide of cell membrane of S. griseus pretreated with and without liposomes under heat stress at 41 degrees C was further carried out. The possible utilization of membrane-membrane interaction between liposomes and cell membrane induced by the heat treatment was further investigated to enhance the production of chitosanase from S. griseus under oxidative stress condition. (C) 2009, The Society for Biotechnology, Japan. All rights reserved.