NOVELTY - A non-naturally occurring polypeptide (A1), comprising a first domain having a combinatorial domain hunting (CDH)-heme domain and a second domain containing a cellulose binding module (CBM), is new.    USE - For degrading cellulose and biomass; and for converting biomass to fermentation product (claimed).    ADVANTAGE - The non-naturally occurring polypeptide reduces the viscosity of a pre-treated biomass mixture; increases the rate of degradation of cellulose; causes less oxidative damage to molecules in a cellulase reaction; and reduces the formation of reactive oxygen species in a cellulase reaction.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the followings:    (1) new recombinant polynucleotide encoding the non-naturally occurring polypeptide (A1);    (2) a composition (C1) comprising a recombinant glycoside hydrolase family 61 (GH61) polypeptide, and a recombinant CDH-heme domain polypeptide containing a CBM;    (3) a composition (C2) comprising a first polypeptide and second polypeptide, where the first polypeptide and second polypeptide stably interact but are not covalently linked;    (4) new host cell comprising recombinant polynucleotides encoding a GH61 polypeptide and a CDH-heme domain polypeptide containing a CBM;    (5) degrading cellulose (M1), involving contacting the cellulose with at least one cellulase and the composition (C1) or (C2), to yield degraded cellulose; or contacting the cellulose with at least one cellulase, a Lewis acid, and a molecule comprising a heme group and containing a CBM, to yield degraded cellulose;    (6) degrading biomass, involving contacting the biomass with at least one cellulase and the composition (C1) or (C2), to yield degraded biomass;    (7) converting (M2) biomass to fermentation product, involving contacting the biomass with at least one cellulase and the composition (C1) or (C2), to yield a sugar solution, and culturing the sugar solution with a fermentative microorganism under conditions sufficient to produce a fermentation product;    (8) increasing the rate of degradation of cellulose in a mixture comprising cellulose and cellulases, involving contacting the mixture comprising cellulose and cellulases with the composition (C1) or (C2);    (9) reducing (M3) the viscosity of a pre-treated biomass mixture, involving contacting the pre-treated biomass mixture with at least one cellulase and the composition (C1) or (C2), to yield a pre-treated biomass mixture having reduced viscosity;    (10) a composition (C3) comprising multiple recombinant GH61 polypeptides, where at least 50% of the GH61 polypeptides are bound to a copper atom;    (11) producing (M4) a GH61 polypeptide, involving culturing a cell comprising a recombinant polynucleotide encoding a GH61 polypeptide in a media that contains 0.1-1000 mu M copper, and subjecting the cell to conditions sufficient to produce GH61 polypeptide from the recombinant polynucleotide encoding the GH61 polypeptide;    (12) degrading (M5) cellulose, involving contacting the cellulose with at least one cellulase, a recombinant CDH-heme domain protein containing a CBM, and a recombinant GH61 polypeptide, where the recombinant GH61 polypeptide comprises: i) a polypeptide of the NCU2240/NCU01050 clade or ii) an amino acid sequence selected from SEQ ID NO: 90 (NCU00836), SEQ ID NO: 26 (NCU07898), or SEQ ID NO: 28 (NCU08760), all are as available on WIPO website, in a reaction mixture, where the method further comprises having a concentration of 0.1-500 mu M copper in the reaction mixture;    (13) increasing the rate of degradation of cellulose in a mixture comprising cellulose, cellulases, a CDH-heme domain polypeptide containing a CMB, and a GH61 polypeptide, involving providing 1-50 mu M copper in the reaction mixture.