Production of CBH1 enzymes. (a) Secreted MULac activity (microM MU released per minute) produced by recombinant strains expressing cbh1 genes cultured in YPD medium for three days. (b) Percentage Avicel hydrolysis by supernatants of the same strains in 24 (grey bars) and 48 (black bars) hours. The values shown are the mean values of three repeats ± standard deviation. (c) Reducing 12% SDS-PAGE of cell free yeast culture supernatants (20 μL) visualized by silver staining. Samples were either deglycosylated with endoH (+) or non-treated (-). Molecular weight markers (97, 66, 45, 30 kDa) are shown on the left. The concentration of total secreted protein (mg/L) as determined by the BioRad protein assay, and the concentration of active CBH1 (mg/L) estimated based on the MULac activity, are indicated by numbers.