title: Fed-batch two-phase production of alanine by a metabolically engineered Escherichia coli.
abstract: DL-Alanine was produced from glucose in an Escherichia coli pfl pps poxB ldhA aceEF pTrc99A-alaD strain which lacked pyruvate-formate lyase, phosphoenolpyruvate (PEP) synthase, pyruvate oxidase, lactate dehydogenase, components of the pyruvate dehydogenase complex and over-produced alanine dehydrogenase (ALD). A two-phase process was developed with cell growth under aerobic conditions followed by alanine production under anaerobic conditions. Using the batch mode, cells grew to 5.3 g/l in 9 h with the accumulation of 6-10 g acetate/l, and under subsequent anaerobic conditions achieved 34 g alanine/l in 13 h with a yield of 0.86 g/g glucose. Using the fed-batch mode at micro = 0.15 h(-1), only about 1 g acetate/l formed in the 25 h required for the cells to reach 5.6 g/l, and 88 g alanine/l accumulated during the subsequent 23 h. This fed-batch process attained an alanine volumetric productivity of 4 g/lh during the production phase, and a yield that was essentially 1 g/g.
authors.affiliation: Center for Molecular BioEngineering, Driftmier Engineering, University of Georgia, Athens, GA 30602, USA.
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Smith
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Lee
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Reilly
authors.forename: Mark A
authors.initials: MA
authors.lastname: Eiteman
authors.forename: Elliot
authors.initials: E
authors.lastname: Altman
mesh_terms: D000332:Aerobiosis; D000409:Alanine / Q000096:biosynthesis*; D050788:Alanine Dehydrogenase / Q000235:genetics / Q000378:metabolism; D000693:Anaerobiosis; D019149:Bioreactors; D004926:Escherichia coli / Q000378:metabolism*; D005285:Fermentation; D011773:Pyruvates / Q000378:metabolism
chemical_list: D011773:Pyruvates; D050788:Alanine Dehydrogenase; D000409:Alanine