Endo-acting xylanase which specifically cleaves internal linkages on the xylan backbone, releasing xylooligosaccharides. Is able to hydrolyze oat spelt xylan, the arabinoxylans from wheat and rye, and glucuronoxylan. Also displays very low activity against xylooligosaccharides. During the xylan degradation process, Xyn10C may act on the soluble xylans and long xylooligosaccharides products released by the secreted xylanases Xyn11A, Xyn11B and Xyn10A. Endohydrolysis of (1->4)-beta-D-xylosidic linkages in xylans. Glycan degradation; xylan degradation. Is predominantly associated with the cell membrane. Induced when the bacterium is cultured on xylan or beta-glucan but not on medium containing mannan. Is repressed by glucose. The N-terminal CBM15 domain binds xylan, including decorated xylans and xylooligosaccharides, but the physiological role of this domain is unclear. It may act as a product capture system: large xylooligosaccharides generated by Xyn10C would bind to CBM15 and this would restrict the diffusion of these polymers into the environment and therefore increase the selective utilization of these molecules by C.japonicus. Xylanase activity resides in the C-terminal domain. Belongs to the glycosyl hydrolase 10 (cellulase F) family.