NOVELTY - A bio-engineered multi-enzyme complex comprises (i) a scaffold polypeptide comprising cohesin domains; and (ii) carbohydrate active enzymes bound to the scaffold polypeptide, each carbohydrate active enzyme comprises a dockerin domain. The carbohydrate active enzymes comprises at least two xylanases. At least one of the xylanases comprises a heterologous dockerin domain.    USE - The bio-engineered multi-enzyme complex, composition and system are used for degrading biomass and for bioconversion of cellulosic material into degradation products (all claimed).    ADVANTAGE - The bio-engineered multi-enzyme complexes comprises at least two xylanases, and optionally other types of carbohydrate active enzymes, designed to attach to a scaffold molecule by the introduction of suitable docking modules. Such complexes are advantageous for degrading recalcitrant cellulosic biomass. The bio-engineered, designer cellulomes show highly synergistic, improved degradative capabilities.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are: (1) a composition for degrading biomass comprising the multi-enzyme complex; (2) a genetically modified host cell comprising a polynucleotide encoding at least one component of the bio-engineered multi-enzyme complex; (3) a cell culture comprising at least one genetically modified host cell, the at least one genetically modified host cell comprising a polynucleotide encoding at least one bio-engineered component of the multi-enzyme complex; (4) a method for bioconversion of cellulosic material into degradation products by exposing the cellulosic material to the multi-enzyme complex; (5) a system for bioconversion of cellulosic material, comprising a multi-enzyme complex; (6) an isolated polypeptide comprising a variant xylanase, the variant comprises a heterologous dockerin domain; (7) an isolated scaffold polypeptide comprising cohesin domains, where the cohesin domains comprises a cohesin derived from Clostridium thermocellum, a cohesin derived from Acetivibrio cellulolyticus and a cohesin derived from Ruminococcus flavefaciens; (8) an isolated scaffold polypeptide comprising cohesin domains, where the cohesin domains comprises a cohesin derived from C. thermocellum, a cohesin derived from A. cellulolyticus, a cohesin derived from R. flavefaciens and a cohesin derived from Bacteroides cellulosolvens; (9) an isolated scaffold polypeptide comprising at least two cohesin domains, where the at least two cohesin domains are selected from (i) a cohesin derived from A. cellulolyticus and a cohesin derived from C. thermocellum (ii) a cohesin derived from B. cellulosolvens and a cohesin derived from R. flavefaciens; and (iii) a cohesin derived from A. cellulolyticus and a cohesin derived from R. flavefaciens; (10) an isolated polynucleotide comprising a sequence encoding the scaffold polypeptide; (11) a construct comprising the polynucleotide of (10); and (12) a host cell comprising the polynucleotide sequence of (10).