Biotechnology Letters

, Volume 30, Issue 11, pp 1943–1946

Indirect monitoring of acetate exhaustion and cell recycle improve lactate production by non-growing Escherichia coli

Original Research Paper

Abstract

A two-phase, lactate fermentation by Escherichia coli ALS974 generates succinate and ethanol anaerobically from acetate. These by-products can be minimized by monitoring acetate concentration indirectly with dissolved O2 (DO) during the initial aerobic cell-growth phase. Without DO monitoring, 3 g succinate/l and 1 g ethanol/l were generated while, with monitoring, less than 1 g succinate/l and no detectable ethanol were generated with 130 g lactate/l being produced. Furthermore, using a cell-recycle fermentation with ultrafiltration prolonged the anaerobic lactate production phase from 22 to 34 h, thereby achieving a lactate productivity of 4.2 g/l h, nearly 20% greater than the productivity of the fed-batch process.

Keywords

Dissolved oxygen Lactate Succinate Ultrafiltration 

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Center for Molecular BioEngineering, Department of Biological and Agricultural EngineeringUniversity of GeorgiaAthensUSA

Personalised recommendations