NOVELTY - A host cell comprising, a recombinant polynucleotide encoding a mutant cellodextrin transporter, where the mutant cellodextrin transporter comprises a transmembrane alpha -helix 1, alpha -helix 2, alpha -helix 3, alpha -helix 4, alpha -helix 5, alpha -helix 6, alpha -helix 7, alpha -helix 8, alpha -helix 9, alpha -helix 10, alpha -helix 11, alpha -helix 12, and a loop sequence positioned between alpha -helix 6 and alpha -helix 7, and where the mutant cellodextrin transporter comprises at least one mutation in the loop sequence, is new.    USE - The host cell is useful for increasing transport of cellodextrin into a cell, and for producing a fermentation product such as a fuel, where the fuel is ethanol (preferred) or butanol (all claimed).    ADVANTAGE - Modified genes that improve the transport of sugars such as cellodextrin, as well as improve the degradation of lignocellulose, and for their use in the engineering of microorganisms for superior growth on lignocellulose and uptake of compounds resulting from lignocellulose degradation; and improved methods of efficient conversion of pentose sugars into biofuels and of mixed sugar fermentation for the production of biofuels are provided.    DETAILED DESCRIPTION - A host cell comprises, a recombinant polynucleotide encoding a mutant cellodextrin transporter, where the mutant cellodextrin transporter comprises a transmembrane alpha -helix 1, alpha -helix 2, alpha -helix 3, alpha -helix 4, alpha -helix 5, alpha -helix 6, alpha -helix 7, alpha -helix 8, alpha -helix 9, alpha -helix 10, alpha -helix 11, alpha -helix 12, and a loop sequence positioned between alpha -helix 6 and alpha -helix 7, where the mutant cellodextrin transporter comprises at least one mutation in the loop sequence, and where the mutant cellodextrin transporter has a Vmax that is at least 1-fold higher than the Vmax of a corresponding cellodextrin transporter lacking the at least one mutation in the loop sequence, is new. INDEPENDENT CLAIMS are:    (1) a method of increasing transport of cellodextrin into a cell by providing the host cell above; and culturing the cell in a medium such that the recombinant polynucleotide is expressed, where expression of the recombinant polynucleotide results in increased transport of cellodextrin into the cell compared to a corresponding cell expressing a recombinant polynucleotide encoding a cellodextrin transporter lacking the at least one mutation in the loop sequence;    (2) an isolated polypeptide comprising an amino acid sequence that is at least 95-100% identical to SEQ ID NO: 2, where the polypeptide comprises an Ala to Asp amino acid substitution at a position corresponding to amino acid 291 of SEQ ID NO: 2;    (3) an isolated polynucleotide encoding the polypeptide of (2);    (4) an expression vector comprising the isolated polynucleotide of (3) operably linked to a regulatory sequence; and    (5) a host cell comprising the expression vector of (4).