TECHNOLOGY FOCUS - BIOLOGY - Preferred Specification: The pH during liquefaction is above 5-6.5, 5-6, or 5-5.5, or 5.2-6.2, or around 5.2, 5.4, 5.6, or 5.8. Preferred Components: The alpha-amylase is chosen from Bacillus, such as a strain of B.stearothermophilus, preferably variant of a B.stearothermophilus alpha -amylase, has a 515 amino acid sequence (SEQ ID NO: 1) fully defined in the specification. The B.stearothermophilus alpha -amylase has a double deletion of positions 1181+G182 and optionally a N193F substitution, or deletion of R179+G180 (using SEQ ID NO: 1 for numbering). The protease is a variant of the metallo protease derived from a strain Thermoascus, preferably T.aurantiacus (CGMCC No:0670). The protease is derived from a strain of Pyrococcus, preferably P.furiosus. The glucoamylase is of fungal origin, preferably from a stain of Aspergillus, preferably A.niger, A.awamori, or A.oryzae, or strain of Trichoderma, preferably T.reesei, or strain of Talaromyces, preferably T.emersonii, or strain of Pycnoporus, or strain of Gloeophyllum, preferably G.sepiarium or G.trabeum or Nigrofomes. The cellulolytic composition is derived from strain of Trichoderma, preferably T.reesei, or strain of Humicola, preferably H.insolens, or strain of Chrysosporium, preferably Chrysosporium lucknowense. The cellulolytic composition is a T.reesei cellulolytic enzyme composition further comprises P.emersonii Glycoside hydrolase family 61 protein A (GH61A) polypeptide having cellulolytic enhancing activity having a 253 amino acid sequence (SEQ ID NO: 23) fully defined in the specification, and A.fumigatus beta-glucosidase having a 863 amino acid sequence (SEQ ID NO: 22) fully defined in the specification or its variants with the following substitutions: F100D, S283G, N456E, F512Y. Preferred Method: The carbohydrate-source generating enzyme present and/or added during liquefaction step (a) is glucoamylase, preferably Penicillium, more preferably Penicillium oxalicum having a 616 amino acid sequence (SEQ ID NO: 9) fully defined in the specification or a 595 amino acid sequence (SEQ ID NO: 14) fully defined in the specification. The glucoamylase is present and/or added during saccharification and/or fermentation. The step (a) involves using alpha -amylase derived from B.stearothermophilus, optionally a protease derived from P.furiosus and/or T.aurantiacus, and P.oxalicum glucoamylase. The step (b) involves using glucoamylase enzyme. EXAMPLE - No suitable example given.