Figure 2.

Cellulase activity can be detected on pure solidified CMC without unwanted artifacts. (A) Assay in petri dish format: Gram’s iodine detection of 5 μg cellulase (Ce), 5 μg amylase (Am) and 5 μg agarase (Ag) spotted onto 7% solidified CMC; and (B,C) Assay in 96-well plate format: Different amounts of cellulase from Aspergillus niger were applied to a gelatinous CMC-layer (4%) in the wells of a 96-well plate. Hydrolysis of the substrate after 16 h of incubation at 27 °C was measured photometrically at 575 nm after Gram’s iodine staining using a microtiter plate reader. Delta (Δ) absorbance values were obtained by deducting the absorbance values of the undigested control wells from those of the sample wells and were plotted against the amount of cellulase (in μg) applied to each well. Error bars in (C) indicate the deviation of the mean value of 13 repetitions.