Test of ChitO-based assay on real substrates. (A) Shrimp shell treated with chitinase from Streptomyces griseus and (B) straw treated with cellulase from Aspergillus niger. Triplicates of the substrate treated with the hydrolase (left) are compared with triplicates of non-treated substrate (right). Images edited to improve contrast. ChitO, chito-oligosaccharide oxidase.