Several recombinant Kluyveromyces marxianus strains were constructed through overexpressing the Neurospora crassa xylose reductase genes. YZJ015, which maintained the original xylitol dehydrogenase gene, produced xylitol with the highest productivity (1.49 g L (1) h (1)) from 100 g L (1) xylose at 42 degrees C. Even at 45 degrees C, YZJ015 was still able to produce 60.03 g L (1) xylitol from 100 g L (1) xylose with a productivity of 1.25 g L (1) h (1). In addition, for 20 rounds of cell recycling at 42 degrees C, YZJ015 produced 71.35 g L (1) xylitol from 100 g L (1) xylose with a productivity of 4.43 g L (1) h (1) per cycle. YZJ017, in which the xylitol dehydrogenase gene was disrupted, produced 100.02 g L (1) xylitol at a yield of 1.01 g g (1) from 100 g L (1) xylose with 40 g L (1) glycerol as co-substrate at 42 degrees C. These engineered strains provide an excellent foundation for xylitol production at elevated temperatures. (C) 2013 Elsevier Ltd. All rights reserved.