Overexpression of GLT1 in fps1DeltagpdDelta mutant for optimum ethanol formation by Saccharomyces cerevisiae.
Glycerol is the main byproduct produced under anaerobic ethanol fermentations by Saccharomyces cerevisiae and consumes a considerable amount of substrate. To verify the metabolic phenotype predications for increasing ethanol formation, two engineered S. cerevisiae KAM-14, KAM-15 strains were constructed for possible redirection of glycerol carbon flux into ethanol by overexpression of GLT1 in the fps1DeltagpdDelta mutant. The engineered strains KAM-14 and KAM-15 compared to the control strain KAM-2, produced 12.24% and 10.42% higher ethanol, 39.72% and 31.03% lower glycerol yield during anaerobic batch fermentations, respectively. The maximum specific growth rates of KAM-14 and KAM-15 were found to be relatively lower than that of KAM-2 during the exponential growth phase. In the meantime, the biomass concentrations of both KAM-14 and KAM-15 were similar to KAM-2. Acetate and pyruvate concentrations of KAM-14 and KAM-15 were greatly decreased comparing to those of KAM-2, respectively. These experimental results approved the metabolic pathway strategies to improve ethanol formation.
Cao
Limin
L
Department of Biochemical Engineering, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China.
Zhang
Aili
A
Kong
Qingxue
Q
Xu
Xiaojing
X
Josine
Tchouopou Lontchi
TL
Chen
Xun
X
D000085:Acetates / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005990:Glycerol / Q000378:metabolism; D009154:Mutation; D011773:Pyruvates / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
D000085:Acetates; D027342:Excitatory Amino Acid Transporter 2; D011773:Pyruvates; D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol; D005990:Glycerol