gTME for improved adaptation of Saccharomyces cerevisiae to corn cob acid hydrolysate

Global transcription machinery engineering was employed to engineer xylose metabolism, tolerance and adaptation to lignocellulosic hydrolysates. Mutation of the transcription factor spt15 was introduced by error-prone PCR, then transformed the recombinant plasmid pYX212-spt15 into Saccharomyces cerevisiae YPH499 which was not able to grow on xylose, and screened on media using lignocellulosic hydrolysates as the sole carbon source. The maximum sugar yield was obtained by the hydrolysis form with 3% HCl (m/v) using autoclaving at 120 °C, for 2 h with a solid to liquid ratio of 1:10. The corn cob hydrolysate contained 68.41 g/L xylose and 7.67 g/L glucose. The recombinant strain showed modest growth rate when cultured in the cellulosic hydrolysates with different pretreatment and pH conditions. The results showed that spt15-29 reached the maximum xylose and glucose utilization of 65.7% and 87.0%, respectively, the maximum ethanol concentration was 11.9 g/L, after 71 h, using the acid hydrolysate with the initial pH of 5.