RESUMO
A preliminary investigation was conducted to assess lignocellulolytic efficiency of crude extracts from three white-rot fungi, Pleurotus florida PF05 (PF), Pleurotus sajor-caju PS07 (PS) and Pleurotus eryngii PE08 (PE). The activities of CMC-ase, xylanase, b-glucosidase, b-xylosidase, laccase and Mn peroxidase in extracts were evaluated. PF produced its highest CMC-ase (317 UL-1), b-glucosidase (62 UL-1), b-xylosidase (37 UL-1) and laccase (347 UL-1) activities while, PS produced highest xylanase (269 UL-1) and Mn peroxidase (69 UL-1) activities. In addition, crude extracts extracted were employed for their in vitro degradability assessment; and were evaluated with mono and mixed extracts separately to corn cob substrate. The losses in cell wall components and dry matter during 5 and 10 days incubations were analyzed after treatments of extracts. Maximum 8.2, 4.4 and 2.8% loss were found respectively in hemicellulose (HC), cellulose (C) and lignin (L) with mono extract of PF within 10 days. The influence of mono extract of each strain (PF, PS and PE) and their mixed extracts (PF+PS, PF+PE, PS+PE and PF+PS+PE) on degradation of cell wall constituents were remarkably differed. The mixed extract treatment proved maximum 13.6% HC loss by PF+PS+PE extract, 9.2% loss in C by PF+PS extract and 5.2% loss of L by the PF+PS+PE extract treatment. The highest dry matter loss (8.2%) was recorded with PF+PS+PE mixed extract combination.