Ptcu1-xyr1 recovered cellulase gene expression on induction by 1% lactose. (A) SDS-PAGE and Western blot analysis of the secreted proteins in the culture supernatant of QM9414 (A) and Ptcu1-xyr1(B) strains grown on 1% (wt/vol) lactose with (lower panel) or without (upper panel) addition of CuSO4. (C) pNPC and pNPG hydrolytic activities of the culture filtrates from QM9414 and Ptcu1-xyr1 strains induced with 1% (wt/vol) lactose and cultured in the presence or absence of CuSO4. A significant difference (P < 0.05) was detected for the culture filtrates of Ptcu1-xyr1 after 72 h without copper addition compared with those of QM9414. Error bars are the SD from at least two biological replicates.