TY - JOUR
T1 - MEP pathway-mediated isopentenol production in metabolically engineered Escherichia coli
AU - Liu, Huaiwei
AU - Wang, Yang
AU - Tang, Qiang
AU - Kong, Wentao
AU - Chung, Wook Jin
AU - Lu, Ting
N1 - Publisher Copyright:
© 2014 Liu et al.; licensee BioMed Central Ltd.
PY - 2014/9/12
Y1 - 2014/9/12
N2 - Background: Isopentenols, such as prenol and isoprenol, are promising advanced biofuels because of their higher energy densities and better combustion efficiencies compared with ethanol. Microbial production of isopentenols has been developed recently via metabolically engineered E. coli. However, current yields remain low and the underlying pathways require systematic optimization.Results: In this study, we targeted the E. coli native 2-methyl-(D)-erythritol-4-phosphate (MEP) pathway and its upstream glycolysis pathway for the optimization of isopentenol production. Two codon optimized genes, nudF and yhfR from Bacillus subtilis, were synthesized and expressed in E. coli W3110 to confer the isopentenol production of the strain. Two key enzymes (IspG and Dxs) were then overexpressed to optimize the E. coli native MEP pathway, which led to a significant increase (3.3-fold) in isopentenol production. Subsequently, the glycolysis pathway was tuned to enhance the precursor and NADPH supplies for the MEP pathway by activating the pentose phosphate pathway (PPP) and Entner-Doudoroff pathway (ED), which resulted in additional 1.9 folds of increase in isopentenol production. A 5 L-scale batch cultivation experiment was finally implemented, showing a total of 61.9 mg L-1 isopentenol production from 20 g L-1 of glucose.Conclusion: The isopentenol production was successfully increased through multi-step optimization of the MEP and its upstream glycolysis pathways. It demonstrated that the total fluxes and their balance of the precursors of the MEP pathway are of critical importance in isopentenol production. In the future, an elucidation of the contribution of PPP and ED to MEP is needed for further optimization of isopentenol production.
AB - Background: Isopentenols, such as prenol and isoprenol, are promising advanced biofuels because of their higher energy densities and better combustion efficiencies compared with ethanol. Microbial production of isopentenols has been developed recently via metabolically engineered E. coli. However, current yields remain low and the underlying pathways require systematic optimization.Results: In this study, we targeted the E. coli native 2-methyl-(D)-erythritol-4-phosphate (MEP) pathway and its upstream glycolysis pathway for the optimization of isopentenol production. Two codon optimized genes, nudF and yhfR from Bacillus subtilis, were synthesized and expressed in E. coli W3110 to confer the isopentenol production of the strain. Two key enzymes (IspG and Dxs) were then overexpressed to optimize the E. coli native MEP pathway, which led to a significant increase (3.3-fold) in isopentenol production. Subsequently, the glycolysis pathway was tuned to enhance the precursor and NADPH supplies for the MEP pathway by activating the pentose phosphate pathway (PPP) and Entner-Doudoroff pathway (ED), which resulted in additional 1.9 folds of increase in isopentenol production. A 5 L-scale batch cultivation experiment was finally implemented, showing a total of 61.9 mg L-1 isopentenol production from 20 g L-1 of glucose.Conclusion: The isopentenol production was successfully increased through multi-step optimization of the MEP and its upstream glycolysis pathways. It demonstrated that the total fluxes and their balance of the precursors of the MEP pathway are of critical importance in isopentenol production. In the future, an elucidation of the contribution of PPP and ED to MEP is needed for further optimization of isopentenol production.
KW - Entner-Doudoroff pathway
KW - Escherichia coli
KW - Isopentenol
KW - MEP pathway
KW - Metabolic engineering
KW - Pentose phosphate pathway (PPP)
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U2 - 10.1186/s12934-014-0135-y
DO - 10.1186/s12934-014-0135-y
M3 - Article
C2 - 25212876
AN - SCOPUS:84910046651
SN - 1475-2859
VL - 13
JO - Microbial cell factories
JF - Microbial cell factories
IS - 1
M1 - 135
ER -