Promotion of extracellular lignocellulolytic enzymes production by restraining the intracellular β-glucosidase in Penicillium decumbens

Abstract In this study, the functions of β-glucosidases in regulation of the lignocellulolytic enzymes production in Penicillium decumbens 114-2 were investigated. The major extracellular β-glucosidase gene bgl1 and the major intracellular β-glucosidase gene bgl2 were deleted in P. decumbens 114-2 respectively. In Δ bgl2 , the production of extracellular lignocellulolytic enzymes (including endoglucanases, cellobiohydrolases and xylanases) on insoluble cellulose was significantly promoted, while in Δ bgl1 there was no any difference compared with that of 114-2. The enhancement of the production of lignocellulolytic enzymes in Δ bgl2 was likely attributed to the accumulation of intracellular cellobiose. Induction experiment in Δ bgl1 Δ 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.