NOVELTY - An isolated or purified polypeptide having improved exoglucanase activity compared to recombinant Hypocrea jecorina exoglucanase 2 protein (CBH2), is new. The CBH2 comprises amino acid sequence of SEQ ID NO: 2. The isolated or purified polypeptide comprises amino acid sequence chosen from amino acid sequences of SEQ ID NOs: 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26 and 28. Sequences not defined here may be found at ftp://ftp.wipo.int/pub/published_pct_sequences/publication.    USE - The isolated or purified polypeptide is useful in enzymatic composition for hydrolyzing cellulose, and producing biofuel. The method (M1) is useful for producing biofuels from lignocellulosic biomass. The method is useful for producing biofuel from biomass (all claimed).    DETAILED DESCRIPTION - An isolated or purified polypeptide having improved exoglucanase activity compared to recombinant Hypocrea jecorina exoglucanase 2 protein (CBH2), is new. The CBH2 comprises amino acid sequence of SEQ ID NO: 2. The isolated or purified polypeptide comprises amino acid sequence chosen from (a) amino acid sequences of SEQ ID NOs: 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26 and 28, and (b) amino acid sequence exhibiting at least 70%, 75%, 80%, 85%, 90%, 95%, 98% or 99% sequence identity to an amino acid sequences of SEQ ID NO: 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26 and 28. Sequences not defined here may be found at ftp://ftp.wipo.int/pub/published_pct_sequences/publication. INDEPENDENT CLAIMS are included for the following:    (1) nucleic acid encoding the above-mentioned isolated or purified polypeptide;    (2) vector comprising at least one the above-mentioned vector;    (3) isolated host cell comprising the above-mentioned nucleic acid, vector or isolated or purified polypeptide;    (4) enzymatic composition comprising the above-mentioned polypeptide and filamentous fungi;    (5) method (M1) for producing biofuels from lignocellulosic biomass; and    (6) method (M2) for producing biofuel from biomass.