[Effects of mutational sptl5 gene to xylose utilization of Saccharomyces cerevisiae].

We used genetic methods to get a mutational spt15 gene from the recombinant strain Saccharomyces cerevisiae YPH499-3, screened by global transcription machinery engineering (gTME) approach. We transformed the gene into the original strain Saccharomyces cerevisiae YPH499 using the vector pYX212, then got a new recombinant strain. We studied the characteristic of this strain and found that it could metabolize xylose and co-ferment xylose and glucose. Under the fermentation condition of 30 degrees C, 200 r/min, 72 h, the utilization ratio of xylose was 82.0%, with 32.4% of ethanol yield when the carbon source in the media was 50 g/L xylose, while the utilization ratio of xylose and glucose was 80.4% and 100% respectively, with the 31.4% of ethanol yield when the carbon source was 50 g/L glucose/xylose (1:1). Meanwhile, the concentration of the by-product xylitol was very low. This study demonstrates the effect which the forward mutation of spt15 gene makes to the co-fermentation of xylose and glucose to ethanol by Saccharomyces cerevisiae.