TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The polypeptide improves the hydrolysis performance of a cellulase composition when the polypeptide constitutes up to 20 wt.% of the cellulase composition, where the improved hydrolysis performance comprises: (a) an increased % glucan conversion, an increased % xylan conversion, and/or an increased % glucan and % xylan conversion from a given lignocellulosic biomass substrate under the same hydrolysis conditions; or (b) an at least 5% faster viscosity reduction of a given lignocellulosic biomass substrate under the same hydrolysis conditions. The polypeptide has an increased beta -mannanase activity as compared to the beta -mannanase activity of BamGh8 comprising SEQ ID NO: 4 (a 360 amino acid sequence fully defined in the specification). The polypeptide has an increased beta -mannanase activity as compared to the beta -mannanase activity of Gte Man1 comprising SEQ ID NO: 5 (a 1047 amino acid sequence fully defined in the specification). The polypeptide retains greater than 70% of the beta -mannanase activity when incubated at a pH of 2.8-7.6. The polypeptide has optimum beta -mannanase activity at a pH of 5. The polypeptide retains at least 80% or more of the beta -mannanase activity when incubated at a temperature of 40-68 degrees C. The polypeptide has optimum beta -mannanase activity at a temperature of 64 degrees C or above. The polypeptide retains at least 50% of the beta -mannanase activity when incubated for 2 hours at a temperature of 82 degrees C. The polypeptide retains at least 99% of the beta -mannanase activity when incubated for 2 hours at a temperature of up to 60 degrees C. The polypeptide comprises an amino acid sequence i.e. at least 60%, preferably at least 70%, identical to the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:3. The cellulases are one or more beta-glucosidases, one or more cellobiohydrolases, or one or more endoglucanases. The other hemicellulases are one or more other beta -mannanases, one or more one or more xylanases, one or more beta -xylosidases, or one or more L-arabinofuranosidases. The polypeptide further comprises a signal peptide sequence. The signal peptide sequence is SEQ ID NOs: 8-36 (one of 29 (16-85) amino acid sequences all fully defined in the specification). The host cell is a bacterial cell or a fungal cell. The lignocellulosic biomass substrate comprises up to 20 wt.% , up to 15%, or up to 10 wt.% of galactoglucomannan and/or glucomannan.    TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preparation: No preparation method is given. EXAMPLE - No suitable example given.