In this study, the functions of beta-glucosidases in regulation of the lignocellulolytic enzymes production in Penicillium decumbens 114-2 were investigated. The major extracellular beta-glucosidase gene bgl1 and the major intracellular B-glucosidase gene bgl2 were deleted in P. decumbens 114-2 respectively. In Delta bgl2, the production of extracellular lignocellulolytic enzymes (including endoglucanases, cellobiohydrolases and xylanases) on insoluble cellulose was significantly promoted, while in Delta bgl1 there was no any difference compared with that of 114-2. The enhancement of the production of lignocellulolytic enzymes in Delta bgl2 was likely attributed to the accumulation of intracellular cellobiose. Induction experiment in Delta bgl1 Delta bgl2 showed that cellobiose was an inducer of lignocellulolytic enzymes expression in P. decumbens 114-2, and the induction was unrelated to the formation, if any, of gentiobiose or sophorose from cellobiose. (C) 2013 Elsevier Ltd. All rights reserved.