A recombinant strain of Saccharomyces cerevisiae containing the bacterial D-xylose isomerase (xylA) gene of Clostridium thermosulfurogenes was constructed. The xylA gene has high thermal stability, functions in an anaerobic environment and has a G+C content of 38.9%, which should render it a good candidate for successful expression in S. cerevisiae. Efficient transcription of the xylA gene under the control of the ADH2 gene promoter and terminator sequences in a recombinant S. cerevisiae strain was shown through Northern Blot analysis. However, the xylA recombinant strain was unable to grow on D-xylose as sole carbon source.