TY - JOUR
T1 - The glucose/xylose facilitator Gxf1 from Candida intermedia expressed in a xylose-fermenting industrial strain of Saccharomyces cerevisiae increases xylose uptake in SSCF of wheat straw
AU - Fonseca, César
AU - Olofsson, Kim
AU - Ferreira, Carla
AU - Runquist, David
AU - Fonseca, Luís L.
AU - Hahn-Hägerdal, Bärbel
AU - Lidén, Gunnar
PY - 2011/5/6
Y1 - 2011/5/6
N2 - Ethanolic fermentation of lignocellulose raw materials requires industrial xylose-fermenting strains capable of complete and efficient d-xylose consumption. A central question in xylose fermentation by Saccharomyces cerevisiae engineered for xylose fermentation is to improve the xylose uptake. In the current study, the glucose/xylose facilitator Gxf1 from Candida intermedia, was expressed in three different xylose-fermenting S. cerevisiae strains of industrial origin. The in vivo effect on aerobic xylose growth and the initial xylose uptake rate were assessed. The expression of Gxf1 resulted in enhanced aerobic xylose growth only for the TMB3400 based strain. It displayed more than a 2-fold higher affinity for d-xylose than the parental strain and approximately 2-fold higher initial specific growth rate at 4g/L d-xylose. Enhanced xylose consumption was furthermore observed when the GXF1-strain was assessed in simultaneous saccharification and co-fermentation (SSCF) of pretreated wheat straw. However, the ethanol yield remained unchanged due to increased by-product formation. Metabolic flux analysis suggested that the expression of the Gxf1 transporter had shifted the control of xylose catabolism from transport to the NAD + dependent oxidation of xylitol to xylulose.
AB - Ethanolic fermentation of lignocellulose raw materials requires industrial xylose-fermenting strains capable of complete and efficient d-xylose consumption. A central question in xylose fermentation by Saccharomyces cerevisiae engineered for xylose fermentation is to improve the xylose uptake. In the current study, the glucose/xylose facilitator Gxf1 from Candida intermedia, was expressed in three different xylose-fermenting S. cerevisiae strains of industrial origin. The in vivo effect on aerobic xylose growth and the initial xylose uptake rate were assessed. The expression of Gxf1 resulted in enhanced aerobic xylose growth only for the TMB3400 based strain. It displayed more than a 2-fold higher affinity for d-xylose than the parental strain and approximately 2-fold higher initial specific growth rate at 4g/L d-xylose. Enhanced xylose consumption was furthermore observed when the GXF1-strain was assessed in simultaneous saccharification and co-fermentation (SSCF) of pretreated wheat straw. However, the ethanol yield remained unchanged due to increased by-product formation. Metabolic flux analysis suggested that the expression of the Gxf1 transporter had shifted the control of xylose catabolism from transport to the NAD + dependent oxidation of xylitol to xylulose.
KW - Bioethanol
KW - Gxf1
KW - Industrial Saccharomyces cerevisiae
KW - Simultaneous saccharification and co-fermentation
KW - Xylose transport
UR - http://www.scopus.com/inward/record.url?scp=79955521875&partnerID=8YFLogxK
U2 - 10.1016/j.enzmictec.2011.02.010
DO - 10.1016/j.enzmictec.2011.02.010
M3 - Journal article
C2 - 22113025
AN - SCOPUS:79955521875
SN - 0141-0229
VL - 48
SP - 518
EP - 525
JO - Enzyme and Microbial Technology
JF - Enzyme and Microbial Technology
IS - 6-7
ER -