Biotechnology Letters

, Volume 28, Issue 20, pp 1695–1700

Fed-batch two-phase production of alanine by a metabolically engineered Escherichia coli

  • Geoffrey M. Smith
  • Sarah A. Lee
  • Kevin C. Reilly
  • Mark A. Eiteman
  • Elliot Altman
Original Paper

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 μ = 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.

Keywords

Acetate Alanine Alanine dehydrogenase Fed-batch process Overflow metabolism 

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Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • Geoffrey M. Smith
    • 1
  • Sarah A. Lee
    • 1
  • Kevin C. Reilly
    • 1
  • Mark A. Eiteman
    • 1
  • Elliot Altman
    • 1
  1. 1.Center for Molecular BioEngineering, Driftmier EngineeringUniversity of GeorgiaAthensUSA

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