A direct interaction of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) liposomes with membrane of Streptomyces griseus cell under the heat stress at 41 degrees C increased the chitosanase production and release to 2.2 times higher than that at 37 degrees C without the POPC liposomes. Amount of chitosanase released across the lipid mimicking cell membrane (LMCM) liposome under a heat at 41 degrees C in the presence of POPC liposomes was 17% of initially-entrapped chitosanase while it was only 1% in the absence of POPC liposomes, even under a heat stress at 41 degrees C, clearly showing the importance of the direct interaction between membrane and membrane.