TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Bio-Engineered Multi-Enzyme Complex: The heterologous dockerin domain replaces at least one of the ancillary modules originally found in the enzyme structure. The heterologous dockerin domain is introduced in addition to the original ancillary modules. The dockerin domain is selected from a dockerin derived from C. thermocellum, a dockerin derived from A. cellulolyticus, a dockerin derived from R. flavefaciens, a dockerin derived from B. cellulosolvens, a dockerin derived from Archaeoglobus fulgidus and a dockerin derived from Clostridium cellulolyticum. The xylanases are classified in a glycoside hydrolase family selected from family 5, 8, 10, 11, 26 and 43. At least one of the xylanases is derived from Thermobifida fusca xylanases, where the T. fusca xylanases are selected from Xyn10B and Xyn11A. The xylanases are selected from a variant Xyn10B comprising a dockerin derived from C. thermocellum, and a variant Xyn11A comprising a dockerin derived from A. cellulolyticus. The scaffold polypeptide comprises one cohesin domain derived from C. thermocellum and one cohesin domain derived from A. cellulolyticus. The carbohydrate active enzymes further comprises at least one carbohydrate active enzyme selected from a glycoside hydrolase, polysaccharide lyase and carbohydrate esterase, where the at least one carbohydrate active enzyme is other than a xylanase, where the at least one carbohydrate active enzyme is a cellulase. The cellulase is classified in a glycoside hydrolase family selected from family 5, 6, 7, 8, 9, 12, 26, 44, 45, 48, 51, 61, and 74. At least one of the cellulases present in the complex is derived from T. fusca cellulases, where the T. fusca cellulases are selected from Cel5A and Cel48A. The cellulases are selected from a variant Cel5A comprising a dockerin derived from R. flavefaciens, and a variant Cel48A comprising a dockerin derived from B. cellulosolvens. The scaffold polypeptide comprises one cohesin domain derived from R. flavefaciens and one cohesin domain derived from B. cellulosolvens. The complex is tri-functional, where the carbohydrate active enzymes comprises two xylanases and one additional carbohydrate active enzyme selected from a glycoside hydrolase, polysaccharide lyase and carbohydrate esterase, where the one additional carbohydrate active enzyme is other than a xylanase. The carbohydrate active enzyme is a cellulase selected from an endocellulase and exocellulase. The complex is quadri-functional, where the carbohydrate active enzymes comprises two xylanases and two additional carbohydrate active enzymes selected from a glycoside hydrolase, polysaccharide lyase and carbohydrate esterase, where the two additional carbohydrate active enzymes are other than xylanases. The quadric-functional complex comprises two xylanases and two cellulases. The scaffold polypeptide further comprises at least one substrate-binding module. Preferred Host Cell: The host cell is selected from a prokaryotic and eukaryotic cell. Preferred Polypeptide: The variant T. fusca xylanase comprises an amino acid sequence selected from SEQ ID NO: 5 and SEQ ID NO: 7. Sequences not defined here may be found at ftp://ftp.wipo.int/pub/published_pct_sequences/publication. EXAMPLE - No suitable example given.