Endo-acting xylanase which specifically cleaves internal linkages on the xylan backbone, releasing xylooligosaccharides. Is also probably able, via its C-terminal domain, to remove acetyl groups from acetylated xylan, and thus it is probably capable of hydrolyzing acetylated xylan. Endohydrolysis of (1->4)-beta-D-xylosidic linkages in xylans. Optimum pH is 5.6. Active from pH 4.0 to 8.0. Optimum temperature is 38 degrees Celsius. Glycan degradation; xylan degradation. Consists of three domains: two complementary catalytic domains and one substrate-binding module. In the later growth phases, seems to undergo a proteolytic cleavage into a 30 kDa protein possessing xylanolytic activity. Could be used as a feed additive for animals in order to diminish health problems due to undigested plant fiber and enhance proliferation of beneficial microflora. Belongs to the glycosyl hydrolase 11 (cellulase G) family.