NOVELTY - Producing ethanol comprises constructing yeast vectors comprising the polynucleotide, transforming a host cell with the vectors to obtain a recombinant yeast strain, and cultivating the recombinant yeast strain in a xylose-containing medium.    USE - The method and polynucleotide are useful for producing ethanol (claimed).    ADVANTAGE - The present invention provides methods and compositions for increased ethanol production. It also provides trains of H. polymorpha with an increased ability to produce ethanol from lignocellulosic starting materials, including the C5 sugar, D-xylose.    DETAILED DESCRIPTION - Producing ethanol comprises (a) isolating from a donor yeast a first polynucleotide comprising a nucleic acid selected from (i) a nucleic acid encoding a polypeptide having pyruvate decarboxylase activity in Hansenula polymorpha and selected from the defined sequence of 571 or 563 amino acids (SEQ ID NO: 1 or 2), an amino acid sequence at least 95% identical to the amino acid sequence of SEQ ID NO: 1 or 2, (ii) the nucleic acid comprising a defined sequence of 1716 or 1692 bp (SEQ ID NO: 3 or 4), or (iii) a nucleic acid 95% identical to SEQ ID NO: 3 or 4, where sequences are given in the specification; (b) constructing yeast vectors comprising the polynucleotide; (c) transforming a host cell with the vectors obtained in step (b) to obtain a recombinant yeast strain; (d) cultivating the recombinant yeast strain in a xylose-containing medium; and (e) isolating and purifying ethanol formed in the medium. INDEPENDENT CLAIMS are: (1) an isolated polynucleotide comprising a nucleic acid selected from (i) a nucleic acid encoding a polypeptide having pyruvate decarboxylase activity in H. polymorpha and selected from the amino acid sequence of SEQ ID NO: 1 or 2, or an amino acid sequence at least 95% identical to the amino acid sequence of SEQ ID NO: 1 or 2, (ii) the nucleic acid of SEQ ID NO: 3 or 4, or (iii) a nucleic acid 95% identical to SEQ ID NO: 3 or 4; (2) an isolated plasmid comprising the polynucleotide; and (3) an isolated host cell comprising the plasmid.