Insoluble dye substrate for screening and assay of xylan-degrading enzymes

A new insoluble dye substrate for xylan degrading enzymes was prepared. Xylan was dyed with Cibacron blue 3GA and cross-linked by 1,4-butanedioldiglycidylether. The substrate was stable at 25°C for 60 h. Xylanase assay by the substrate was more sensitive than conventional dinitrosalicylic acid method and was not interfered with by a reducing sugar. The substrate could be used for simple and sensitive measurement of xylanase activities and preparation of agar plates for screening of xylanase producing microorganisms.