Secondary walls in dicot plants contain approximately 20 % (w/w) xylan. Xylan found in those species is mainly glucuronoxylan (GX), where the xylan backbone is decorated with α-1,2-linked glucuronic acid (GlcA) and 4-O-methyl-glucuronic acid (MeGlcA) to about 10 % (Ebringerová 2005; Keppler and Showalter 2010).