NOVELTY - Isolated protein (I), comprising: a domain having an amino acid sequence of at least 70%, preferably 100% identical to amino acids 250-580 of SEQ ID NO: 1, where (I) is a cellulase; an amino acid sequence encoded by a nucleic acid sequence with at least 70%, preferably 100% identity to SEQ ID No. 2-4, or SEQ ID No. 15; an amino acid sequence encoded by a nucleic acid sequence with at least 70%, preferably 100% identity to SEQ ID No. 2-4, or SEQ ID No. 15; and amino acids 250-580 of SEQ ID NO: 1, where sequences not defined here may be found at ftp://ftp.wipo.int/pub/published-pct-sequences/pu    USE - (I) is useful for: reducing the viscosity of a pretreated biomass mixture; converting a biomass to sugars; producing a fermentation product; and producing a fuel and food. (I) is useful as laundry detergent composition for cleaning, anti-deposition and color care textile (all claimed).    ADVANTAGE - (I) is stable.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) an isolated mature cellulase protein, comprising the amino acid sequence having at least 70%, preferably 100% identity to amino acids 5-842, 10-842, 15-842, 20-842, 24-482, 25-482, 30-842, 35-842, 40-842, 45-842, 50-842, or 130-842 of SEQ ID No. 1;    (2) a method for producing (I);    (3) a composition comprising (I), host cell and culture medium, or (I) in supernatant of culture medium;    (4) an isolated nucleic acid encoding (I);    (5) an expression vector, comprising the isolated nucleic acid, operably linked to a regulatory sequence;    (6) the host cell, comprising the expression vector;    (7) a method of reducing the viscosity of a pretreated biomass mixture, comprising contacting a pretreated biomass mixture having an initial viscosity with the composition, and incubating the contacted biomass mixture under conditions sufficient to reduce the initial viscosity of the pretreated biomass mixture;    (8) a method of converting a biomass to sugars comprising contacting the biomass with the composition;    (9) a method of hydrolyzing or degrading a biomass, comprising contacting the biomass with the composition;    (10) a method of producing a fermentation product, comprising (a) contacting the biomass with the composition to form a first product, and (b) culturing the first product with one or more fermentive microorganisms under conditions sufficient to produce a fermentation product, or (a1) hydrolyzing or degrading biomass with the composition to form a first product, and the step (b), or the step (a1), and incubating the first product with a chemical solution, under conditions sufficient to produce a fermentation product by a chemical process;    (11) a method of fermenting biomass, comprising fermenting the biomass with one or more fermenting microorganisms, where the biomass is treated by the composition;    (12) a method of producing a fuel comprising (A1) contacting a biomass with the composition to yield a sugar solution, and culturing the sugar solution with a fermentative microorganism under conditions sufficient to produce a fuel, or the step (A1), and incubating the sugar solution with a chemical solution, under conditions sufficient to produce a fermentation product by a chemical process;    (13) a method of food production, comprising contacting a plant material with the composition to yield a treated plant material;    (14) a method of textile cleaning comprising contacting a soiled textile with the composition to yield clean textile; and    (15) a method of paper pulp bleaching comprising contacting paper pulp with the composition to yield bleached paper pulp.