Open AccessHigh Glycolytic Flux Improves Pyruvate Production by a Metabolically Engineered Escherichia coli Strain
Author(s) -
Yihui Zhu,
Mark A. Eiteman,
Ronni Altman,
Elliot Altman
Publication year - 2008
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.01610-08
Subject(s) - pyruvate dehydrogenase complex , biochemistry , pyruvate decarboxylation , chemostat , pyruvate dehydrogenase phosphatase , pyruvate dehydrogenase kinase , biology , escherichia coli , glycolysis , pyruvate carboxylase , chemistry , metabolism , enzyme , bacteria , gene , genetics
We report pyruvate formation inEscherichia coli strain ALS929 containing mutations in theaceEF ,pfl ,poxB ,pps , andldhA genes which encode, respectively, the pyruvate dehydrogenase complex, pyruvate formate lyase, pyruvate oxidase, phosphoenolpyruvate synthase, and lactate dehydrogenase. The glycolytic rate and pyruvate productivity were compared using glucose-, acetate-, nitrogen-, or phosphorus-limited chemostats at a growth rate of 0.15 h−1 . Of these four nutrient limitation conditions, growth under acetate limitation resulted in the highest glycolytic flux (1.60 g/g · h), pyruvate formation rate (1.11 g/g · h), and pyruvate yield (0.70 g/g). Additional mutations inatpFH andarcA (strain ALS1059) further elevated the steady-state glycolytic flux to 2.38 g/g · h in an acetate-limited chemostat, with heterologous NADH oxidase expression causing only modest additional improvement. A fed-batch process with strain ALS1059 using defined medium with 5 mM betaine as osmoprotectant and an exponential feeding rate of 0.15 h−1 achieved 90 g/liter pyruvate, with an overall productivity of 2.1 g/liter · h and yield of 0.68 g/g.