TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Biomass Saccharification Mixture: The level of saccharification is measured by the yield of fermentable sugar after the mixture is incubated for a period of time sufficient to cause saccharification of the biomass. The glycosyl hydrolase family 61 enzyme is derived from a filamentous fungus selected from, but not limited to, Trichoderma, Humicola, Fusarium, Aspergillus, Neurospora, Penicillium, Cephalosporium, Achlya, Podospora, Endothia, Mucor, Cochliobolus, Pyricularia, and Chrysosporium. The enzyme composition further comprises at least one polypeptide having cellobiohydrolase activity and at least one polypeptide having beta -glucosidase activity. At least one polypeptide having cellobiohydrolase activity is a polypeptide encoding a Trichoderma reesei CBH1, Af7A (SEQ ID NO: 150), Af7B (SEQ ID NO: 151), Cg7A (SEQ ID NO: 152), Cg7B (SEQ ID NO: 153), Tt7A (SEQ ID NO: 154), Tt7B (SEQ ID NO: 155), T. reesei CBH2, Tt6A (SEQ ID NO: 156), St6A (SEQ ID NO: 157), St6B (SEQ ID NO: 158), or its variant having at least 90% sequence identity to the stated sequences. At least one polypeptide having beta -glucosidase activity is: (i) a polypeptide encoding an Fv3C (SEQ ID NO: 100), a Pa3D (SEQ ID NO: 94), an Fv3G (SEQ ID NO: 96), an Fv3D (SEQ ID NO: 98), a Tr3A (SEQ ID NO: 102), a Tr3B (SEQ ID NO: 104), a Te3A (SEQ ID NO: 106), an An3A (SEQ ID NO: 108), an Fo3A (SEQ ID NO: 110), a Gz3A (SEQ ID NO: 112), an Nh3A (SEQ ID NO: 114), a Vd3A (SEQ ID NO: 116), a Pa3G (SEQ ID NO: 118), a Tn3B (SEQ ID NO: 119), or its variant having at least 90% sequence identity to the stated sequences; or (ii) a polypeptide encoded by a polynucleotide (1) having at least 90% sequence identity to SEQ ID NO: 99, 93, 95, 97, 101, 103, 105, 107, 109, 111, 113, 115, or 117; (2) hybridizes under high stringency conditions to SEQ ID NO: 99, 93, 95, 97, 101, 103, 105, 107, 109, 111, 113, 115, or 117, or to a complement. The enzyme composition further comprises one or more or all of: (1) a polypeptide having xylanase activity, (2) a polypeptide having beta -xylosidase activity; and (3) a polypeptide having L- alpha -arabinofuranosidase activity. The polypeptide having xylanase activity is: (i) a polypeptide encoding a T. reesei Xyn3 (SEQ ID NO: 76), T. reesei Xyn2 (SEQ ID NO: 77), an AfuXyn2 (SEQ ID NO: 58), and AfuXyn5 (SEQ ID NO: 60), or its variant having at least 90% sequence identity to the stated sequences; or (ii) a polypeptide encoded by a polynucleotide (1) having at least 90% sequence identity to SEQ ID NO: 75, 57, or 59; or (2) hybridizes under high stringency conditions to SEQ ID NO: 75, 57, or 59, or to a complement. At least one polypeptide having beta -xylosidase activity is: (i) a polypeptide encoding an Fv3A (SEQ ID NO: 36), an Fv43A (SEQ ID NO: 44), a Pf43A (SEQ ID NO: 38), an Fv43D (SEQ ID NO: 62), an Fv39A (SEQ ID NO: 42), an Fv43E (SEQ ID NO: 40), an Fo43A (SEQ ID NO: 52), an Fv43B (SEQ ID NO: 46), a Pa51A (SEQ ID NO: 48), a Gz43A (SEQ ID NO: 50), a T. reesei BxI1 (SEQ ID NO: 78), or its variant having at least 90% sequence identity to the stated sequences; or (ii) a polypeptide encoded by a polynucleotide (1) having at least 90% sequence identity to SEQ ID NO: 35, 43, 37, 61, 41, 39, 51, 45, 47, 49, or 159; (2) hybridizes under high stringency conditions to SEQ ID NO: 35, 43, 37, 61, 41, 39, 51, 45, 47, 49, 159, or to a complement. At least one polypeptide having L- alpha -arabinofuranosidase activity is: (i) a polypeptide encoding an Af43A (SEQ ID NO: 54), an Fv43B (SEQ ID NO: 46), a Pf51A (SEQ ID NO: 56), a Pa51A (SEQ ID NO: 48), an Fv51A (SEQ ID NO: 66), or its variant having at least 90% sequence identity to the stated sequences; or (ii) a polypeptide encoded by a polynucleotide (1) having at least 90% sequence identity to SEQ ID NO: 53, 45, 55, 47, or 65; (2) hybridizes under high stringency conditions to SEQ ID NO: 53, 45, 55, 47, or 65, or to a complement. The enzyme composition comprises (1) 0.1-50 wt.%, 1-20 wt.%, 5-15 wt.% of the polypeptide having GH61/endoglucanase activity, referencing the total weight of proteins in the enzyme composition; or (2) 0.2-30 mg, 0.2-20 mg, 0.5-10 mg, or 1-5 mg of the polypeptide having GH61/endoglucanase activity per gram of cellulose, hemicelluloses or a mixture of cellulose and hemicelluloses contained in the biomass material. The enzyme composition comprises cellulobiohydrolase in an amount that is (1) 0.1-80 wt.%, 5-70 wt.%, 10-60 wt.%, 20-50 wt.%, or 25-50 wt.% of the total weight of proteins in the enzyme composition; or (2) 0.2-30 mg, 0.2-20 mg, 0.5-10 mg, or 0.5 mg to 5 mg per gram of cellulose, hemicelluloses, or a mixture of cellulose and hemicelluloses in the biomass saccharification mixture; and comprises beta -glucosidase in an amount that is (1) 0.1-50 wt.%, 1-30 wt.%, 2-20 wt.%, 5-20 wt.%, or 8-15 wt.% of the total weight of proteins in the enzyme composition; or (2) 0.2-30 mg, 0.2-20 mg, 0.5-10 mg, or 0.5-5 mg per gram of cellulose, hemicelluloses, or a mixture of cellulose and hemicelluloses in the biomass saccharification mixture. The enzyme composition comprises (1) 0.1-50 wt.%, 1-40 wt.%, 4-30 wt.%, 5-20 wt.%, or 8-15 wt.% of the polypeptide having xylanase activity, referencing the total weight of proteins in the enzyme composition; or (2) 0.2-30 mg, 0.2-20 mg, 0.5-10 mg, or 0.5-5 mg of the polypeptide having xylanase activity per gram of cellulose, hemicelluloses, or a mixture of cellulose and hemicelluloses in the biomass saccharification mixture. The enzyme composition comprises (1) 0.1-50 wt.%, 1-40 wt.%, 2-30 wt.%, 4-20 wt.%, or 5-15 wt.% of the polypeptide having beta -xylosidase activity, referencing the total weight of proteins in the enzyme composition; or (2) 0.2-30 mg, 0.2-20 mg, 0.5-10 mg, or 0.5-5 mg of the polypeptide having beta -xylosidase activity per gram of cellulose, hemicelluloses, or a mixture of cellulose and hemicelluloses in the biomass saccharification mixture. The enzyme composition comprises (1) 0.1-50 wt.%, 0.1-50 wt.%, 1-40 wt.%, 2-30 wt.%, 4-20 wt.%, or 5-15 wt.% of the polypeptide having L- alpha -arabinofuranosidase activity, referencing the total weight of proteins in the enzyme composition; or (2) 0.2-30 mg, 0.2-20 mg, 0.5-10 mg, or 0.5-5 mg of the polypeptide having L- alpha -arabinofuranosidase activity per gram of cellulose, hemicelluloses, or a mixture of cellulose and hemicelluloses in the biomass saccharification mixture. The enzyme composition is a whole cellulase composition, where the whole cellulase composition is derived from a host cell expressing a polynucleotide encoding a polypeptide having GH61/endoglucanase activity, and where the polynucleotide encoding the polypeptide having GH61 family enzyme activity is heterologous to the host cell. The whole cellulase composition is derived from a host cell further expressing a polynucleotide encoding a polypeptide having cellobiohydrolase activity, and a polynucleotide encoding a polypeptide having beta -glucosidase activity, where the polynucleotide encoding the polypeptide having cellobiohydrolase activity and/or the polynucleotide encoding the polypeptide having beta -glucosidase are heterologous to the host cell. The whole cellulase composition is derived from a host cell expressing one or more or all of (1) a polynucleotide encoding a peptide having beta -xylosidase activity; (2) a polynucleotide encoding a polypeptide having xylanase activity; and (3) a polynucleotide peptide having L- alpha -arabinofuranosidase activity, where the polynucleotide encoding the polypeptide having beta -xylosidase activity, the polynucleotide encoding the polypeptide having xylanase activity, or the polynucleotide encoding the polypeptide having L- alpha -arabinofuranosidase activity is heterologous to the host cell. The enzyme composition is a whole broth formulation. One or more or all of: (1) the gene encoding the polypeptide having GH61/endoglucanase activity; (2) the gene encoding the polypeptide having cellobiohydrolase activity; (3) the gene encoding the polypeptide having beta -glucosidase activity; (4) the gene encoding the polypeptide having beta -xylosidase activity; (5) the gene encoding the polypeptide having xylanase activity; and (6) the gene encoding the polypeptide having L- alpha - arabinofuranosidase activity are integrated into the genetic material of the host cell. The host cell is a bacterial host cell, yeast host cell, or a fungal host cell. The host cell is a filamentous fungal host cell from, but not limited to, Aspergillus niger, Aspergillus oryzae, Chrysosporium lucknowense, Fusarium cerealis, Fusarium graminearum, Ceriporiopsis caregiea, Ceriporiopsis gilvescens, Humicola lanuginosa, Mucor miehei, and Myceliophthora thermophila. The saccharification mixture is prepared by first blending the enzyme composition comprising the polypeptide having GH61/endoglucanase activity, followed by mixing the enzyme composition with the biomass. The biomass material comprises hemicellulose, cellulose, or a mixture of hemicelluloses and cellulose. The biomass material comprises glucan, xylan and/or lignin. The biomass material is subjected to pretreatment with an acid or a base, where the pretreated biomass is adjusted to pH of 4.0 to 6.5 before mixing with the enzyme composition. The biomass material is present in the mixture in an amount of 5-60 wt.%, 10-50 wt.%, 15-40 wt.%, 15-30 wt.%, or 20-30 wt.%, referring to the amount of biomass material in its solid state relative to the total weight of the mixture. Sequences not defined here may be found at ftp://ftp.wipo.int/pub/published_pct_sequences/publication. Preferred Method: In the method of hydrolyzing a biomass material, the conditions suitable for hydrolyzing the biomass materials in the biomass saccharification mixture comprises: (1) a pH of 3.5-7.0; (2) for 2 hours or longer; and/or (3) a temperature of 20-75 degrees C. The sufficient period of time comprises a time period of 8-72 hours. At any given time above 2 hours, the amount of fermentable sugars is produced by the biomass saccharification mixture is increased by at least 5% as compared to the amount of fermentable sugars produced by a control biomass saccharification mixture comprising the same amount and type of biomass material, and the same composition of enzyme components but in the absence of the GH61/endoglucanase. The amount of fermentable sugars produced by the biomass saccharification is increased by at least 10%, as compared to the fermentable sugars produced by the control biomass saccharification mixture. The biomass material is present in an amount of 10-50 wt.% in its solid state. The viscosity of the biomass saccharification mixture is reduced by at least 5%, 10%, 15%, 20%, 25%, or more, as compared to the viscosity of the control biomass saccharification mixture comprising the same amount and type of biomass material, and the same composition of enzyme components but in the absence of the GH61/endoglucanase. EXAMPLE - No suitable example given.