The increasing demand for and the necessity of using sustainable resources require the further development of alternative technologies. The project "CrossCat - Symbiosis of bio- & chemo-catalysts for the sustainable conversion of hemicelluloses" deals with the utilization of the hemicellulose fraction, especially xylan. In an example process for combining of biological and chemical catalysts in a one-pot process, xylan shall first be hydrolyzed to xylose and then hydrogenated to xylitol. To make this possible, suitable immobilization of the xylanases is required. For this purpose, the xylanases were immobilized covalently using glutaraldehyde (GDA) on various carrier materials with and without surface functionalization and activation. Immobilization on uncoated stainless steel hollow spheres with simultaneous covalent binding to the surface and cross-linking of the enzymes was most suitable for later use. The produced immobilizates showed an increased long-term stability (57 % residual activity after 24 h) compared to free enzymes (8 %) and could be used for several days (4?6 d) for the hydrolysis of xylan to xylose.