Cellulolytic enzyme assays of engineered yeasts. (A) CBH relative activity with PASC as the sole substrate. (B) EG relative activity with CMC as the sole substrate. (C) BGL relative activity assay with pNPG as the sole substrate. (D) Total specific cellulase activity assay with filter paper as the sole carbon substrate. The samples collected from KY3, KR5 and KR7 cultures were estimated using the same protein concentration for enzyme reaction at 40°C. One unit of FPA is defined as one mmol reducing sugar releasing from filter paper in one minute. *: P < 0.05 (significant), **: P < 0.01; ***: P < 0.001; N.S., non-significant.