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Altered regulation of pyruvate kinase or co‐overexpression of phosphofructokinase increases glycolytic fluxes in resting Escherichia coli
Author(s) -
Emmerling Marcel,
Bailey James E.,
Sauer Uwe
Publication year - 2000
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(20000305)67:5<623::aid-bit13>3.0.co;2-w
Subject(s) - pyruvate kinase , phosphofructokinase , zymomonas mobilis , glycolysis , biochemistry , allosteric regulation , anaerobic glycolysis , heterologous , anaerobic exercise , kinase , biology , flux (metallurgy) , metabolism , escherichia coli , chemistry , enzyme , ethanol , ethanol fuel , gene , physiology , organic chemistry
Glycolytic fluxes in resting Escherichia coli were enhanced by overexpression of heterologous pyruvate kinases (Pyk) from Bacillus stearothermophilus and Zymomonas mobilis , but not homologous Pyk. Compared to the control, an increase of 10% in specific glucose consumption and of 15% in specific ethanol production rates was found in anaerobic resting cells, expressing the heterologous Pyks, that were harvested from exponentially growing aerobic cultures. A further increase in glycolytic flux was achieved by simultaneous overexpression of E. coli phosphofructokinase (Pfk) and Pyk with specific glucose consumption and ethanol production rates of 25% and 35% greater, respectively, than the control. Fluxes to lactate were not significantly affected, contrary to previous observations with resting cells harvested from anaerobically growing cultures. To correlate the physiology of resting cells with the physiology of cells prior to harvest, we determined the relevant growth parameters from aerobic and anaerobic precultures. We conclude that glycolytic fluxes in E. coli with submaximal (aerobic) metabolic activity can be increased by overexpression of pyruvate kinases which do not require allosteric activation or co‐overexpression with Pfk. However, such improvements require more extensive engineering in E. coli with near maximal (anaerobic) metabolic activity. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 67: 623–627, 2000.