60 mL of non-concentrated periplasmic fraction from Prevotella bryantii cultivation medium were subjected to two-step purification on CIM® DEAE 8 mL tube. Both purification steps were performed under similar chromatographic conditions, i.e. same column, buffer systems and flow rate (7 mL/min). Gradient slopes varied to achieve isolation of the desired fraction. The elution fraction of interest of purification No1 was subjected to a second purification on the same column. By altering the linear gradient pure 66 kDa-Endoxylanase for production of antibodies was isolated.