An extractive liquid-surface immobilization (Ext-LSI) system with a fungal mat formed on the surface of a liquid medium effectively enabled derepression of carbon catabolite repression. In this system, a fungicidal secondary metabolite 6-pentyl-alpha-pyrone was efficiently produced by Trichoderma atroviride AG2755-5NM398 despite the addition of 25% glucose or fructose. (C) 2012, The Society for Biotechnology, Japan. All rights reserved.