Characterization of β-glucosidase (BGL)-displaying yeast strains. (A) Time course of transcriptional levels of BGL1. The relative BGL1 level of each sample is shown as a fold change in the mRNA level from the average of BY-BG-TA in 24 h. (B) Time course of BGL activities. (C) Immobilizing ratios of BGL activity. The immobilizing ratio was calculated by dividing the activity of the cell by the total activity of the culture medium, including the culture supernatant. Error bars indicate the standard deviations of three independent experiments.