NOVELTY - A substantially purified chimeric polypeptide (p1) comprising at least two domains from at least two different parental cellobiohydrolase I (CBHI) polypeptides, is new.    USE - For treating a biomass comprising cellulose (claimed).    ADVANTAGE - The chimeric polypeptide has cellobiohydrolase activity and improved thermostability, pH stability and/or expression compared to a CBHI polypeptide comprising (SEQ ID NO: 2, 4, 6, 8 or 10) all as available on WIPO website. The observed improvements in chimera properties and the high fraction of active recombined enzymes show that SCHEMA recombination is applied to enzymes that contain extensive posttranslational modifications. As such, these results are relevant not only to enzyme engineering in the context of industrial biomass conversion processes but also for engineering other proteins for which high sequence diversity is desirable and/or whose properties are not easily improved by mutagenesis and high throughput screening.    DETAILED DESCRIPTION - A substantially purified chimeric polypeptide (p1) comprising at least two domains from at least two different parental cellobiohydrolase I (CBHI) polypeptides, is new. The domains comprise from N- to C- terminus: (s1)-(s2)-(s3)-(s4)-(s5)-(s6)-(s7)-(s8). The chimeric polypeptide has cellobiohydrolase activity and improved thermostability, pH stability and/or expression compared to a CBHI polypeptide comprising (SEQ ID NO: 2, 4, 6, 8 or 10) all as available on WIPO website.    s1=segment comprising a sequence that is at least 50-100% identical to amino acid residue from 1 or 18 or 19 to x1 of T1;    T1=(SEQ ID NO: 2) ('1'), (SEQ ID NO: 4) ('2'), (SEQ ID NO: 6) ('3'), (SEQ ID NO: 8) ('4'), or (SEQ ID NO: 10) ('5'), all as available on WIPO website;    s2=segment comprising a sequence that is at least 50-100% identical to amino acid residue x1 to x2 of T1;    s3=segment comprising a sequence that is at least 50-100% identical to amino acid residue x2 to x3 of T1;    s4=segment comprising a sequence that is at least 50-100% identical to amino acid residue x3 to x4 of T1;    s4=segment comprising a sequence that is at least 50-100% identical to amino acid residue x4 to x5 of T1;    s6=segment comprising a sequence that is at least 50-100% identical to amino acid residue x5 to x6 of T1;    s7=segment comprising a sequence that is at least 50-100% identical to amino acid residue x6 to x7 of T1;    s8=segment comprising a sequence that is at least 50-100% identical to amino acid residue x7 to x8 of T1;    x1=residue 47, 48, 49, 50, 51, or 52 of (SEQ ID NO:2, 4, 6, or 8), or residue 48, 49, 50, 51, 52 or 53 of (SEQ ID NO: 10);    x2=residue 92, 93, 94 95, 96 or 97 of (SEQ ID NO: 2 or 10), or residue 91, 92, 93, 94, 95, or 96 of (SEQ ID NO: 4, 6, or 8);    x3=residue 127, 128, 129, 130, 131 or 132 of (SEQ ID NO: 2), or residue 125, 126, 127, 128, 129 or 130 of (SEQ ID NO: 4 or 6), or residue 126, 127, 128, 129, 130 or 131 of (SEQ ID NO: 8), or residue 123, 124, 125, 126, 127 or 128 of (SEQ ID NO: 10);    x4=residue 175, 176, 177, 178, 180 or 181 of (SEQ ID NO: 2), or residue 173, 174, 175, 176, 177 or 178 of (SEQ ID NO: 4 or 6), or residue 174, 175, 176, 177, 178 or 179 of (SEQ ID NO: 8), or residue 171, 172, 173, 174, 175 or 176 of (SEQ ID NO: 10);    x5=residue 221, 222, 223, 224, 225 or 226 of (SEQ ID NO: 2), or residue 219, 220, 221, 222, 223 or 224 of (SEQ ID NO: 4 or 6), or residue 220, 221, 222, 223, 224 or 225 of (SEQ ID NO: 8), or residue 217, 218, 219, 220, 221 or 222 of (SEQ ID NO: 10);    x6=residue 268, 269, 270, 271, 272 or 273 of (SEQ ID NO: 2), or residue 266, 267, 268, 269, 270 or 271 of (SEQ ID NO: 4 or 6), or residue 267, 268, 269, 270, 271 or 272 of (SEQ ID NO: 8), or residue 264, 265, 266, 267, 268 or 269 of (SEQ ID NO: 10);    x7=residue 384, 385, 386, 387, 388 or 389 of (SEQ ID NO: 2), or residue 385, 386, 387, 388, 389 or 390 of (SEQ ID NO: 4), or residue 378, 379, 380, 381, 382 or 383 of (SEQ ID NO: 6), or residue 383, 384, 385, 386, 387 or 388 of (SEQ ID NO: 8 or 10);    x8=an amino acid residue corresponding to residue 454 of (SEQ ID NO: 2), residue 457 of (SEQ ID NO: 4), residue 458 of (SEQ ID NO: 6), residue 453 of (SEQ ID NO: 8), residue 455 of (SEQ ID NO: 10) or the C-terminus of the polypeptide having the sequence of (SEQ ID NO: 2, 4, 6, 8 or 10).    INDEPENDENT CLAIMS are included for the following:    (1) a polynucleotide encoding the polypeptide (p1);    (2) a vector comprising the polynucleotide;    (3) a host cell comprising the vector;    (4) an enzymatic preparation comprising the polypeptide;    (5) treating a biomass comprising cellulose, involving contacting the biomass with the enzymatic preparation, or the host cell; and    (6) preparation of the polypeptide (p1).