Xylose utilization is one of the key issues in lignocellulose bioconversion.Because of glucose repression,in most engineered yeast with heterogeneous xylose metabolic pathway,xylose is not consumed until glucose is co...Xylose utilization is one of the key issues in lignocellulose bioconversion.Because of glucose repression,in most engineered yeast with heterogeneous xylose metabolic pathway,xylose is not consumed until glucose is completely utilized.Although simultaneous glucose and xylose utilization have been achieved in yeast by RPE1 deletion,we regulated ZWF1 and PGI1 transcription to improve simultaneous xylose and glucose utilization by controlling the metabolic flux from glucose into the PP pathway.Xylose and glucose consumption increased by approximately 80 and 72%,respectively,whereas ZWF1 was overexpressed by multi-copy plasmids with a strong transcriptional promoter.PGI1 expression was knocked down by promoter replacement; the glucose and xylose metabolism increased when PGI1p was replaced by weak promoters,SSA1p and PDA1p.ZWF1 overexpression decreased while PGI1 down-regulation increased the ethanol yield to some extent in the recombinant strains.展开更多
基金supported by the National Basic Research Program of China(‘‘973’’Program,No.2013CB733601)the National High Technology Research and Development Program of China(‘‘863’’Program,No.2012AA02A701)+1 种基金the National Natural Science Foundation of China(No.21390203)the Tianjin Municipal Science and Technology Committee(No.13RCGFSY19800)
文摘Xylose utilization is one of the key issues in lignocellulose bioconversion.Because of glucose repression,in most engineered yeast with heterogeneous xylose metabolic pathway,xylose is not consumed until glucose is completely utilized.Although simultaneous glucose and xylose utilization have been achieved in yeast by RPE1 deletion,we regulated ZWF1 and PGI1 transcription to improve simultaneous xylose and glucose utilization by controlling the metabolic flux from glucose into the PP pathway.Xylose and glucose consumption increased by approximately 80 and 72%,respectively,whereas ZWF1 was overexpressed by multi-copy plasmids with a strong transcriptional promoter.PGI1 expression was knocked down by promoter replacement; the glucose and xylose metabolism increased when PGI1p was replaced by weak promoters,SSA1p and PDA1p.ZWF1 overexpression decreased while PGI1 down-regulation increased the ethanol yield to some extent in the recombinant strains.
