Cellobiohydrolases Produce Different Oligosaccharides from Chitosan

Chito-oligosaccharides (COSs) are bioactive molecules with interesting characteristics; however, their exploitation is still restricted due to limited amounts accessible with current production strategies. Here we present a strategy for the production of COSs based on hydrolysis of chitosan by using readily available glycosidases. Cellobiohydrolases (EC 3.2.1.91) were compared with chitosanases (EC 3.2.1.132) regarding their ability for COS production, and the resulting fractions were analyzed by MS and NMR. The oligosaccharides had a degree of polymerization between three and six units, and the degree of acetylation (DA) varied depending on the applied enzyme. Different cellobiohydrolases produced COSs with varying DA, and based on comprehensive NMR analysis the preferred cleavage sites of the respective enzymes that show chitosanase and chitinase activity were elucidated. The study reveals the high potential of readily available cellulolytic enzymes besides chitosanases for the production of COSs with distinct structure facilitating access to this bioactive compound class.