Aerobic succinate production in bacteria
Methods of increasing yields of succinate using aerobic culture methods and a multi-mutant E. coli strain are provided. Also provided is a mutant strain of E. coli that produces high amounts of succinic acid.
1. A method of aerobically producing succinate comprising:
a) generating a genetically engineered E. coli strain comprising:
i) reduced activity of succinate dehydrogenase (sdhAB), acetate kinase (ackA), phosphotransacetyloase (pta) or both ackA-pta, and
ii) reduced activity of pyruvate oxidase (poxB); and
iii) reduced activity of aceBAK operon repressor (iclR); and
iv) reduced activity of phosphotransferase system gene (ptsG), and
v) increased activity of phosphoenolpyruvate carboxylase (pepc); and
b) culturing said bacteria in a fed-batch reactor so that said bacteria produce at least 500 mM succinate.
2. The method of claim 1 , wherein said bacterial strain comprises a deletion of one or more genes selected from the group consisting of sdh, ackA, pta, poxB, iclR and ptsG.
3. The method of claim 1 , wherein said bacterial strain comprises a knockout of one or more genes selected from the group consisting of sdh, ackA, pta, poxB, iclR and ptsG.
4. The method of claim 1 , wherein said bacterial strain further comprises an expression vector encoding pepc.