Indirect monitoring of acetate exhaustion and cell recycle improve lactate production by non-growing Escherichia coli.
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 O(2) (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.
Center for Molecular BioEngineering, Department of Biological and Agricultural Engineering, University of Georgia, Athens, GA, 30602, USA.
Yihui
Y
Zhu
Mark A
MA
Eiteman
Elliot
E
Altman
D000085:Acetates / Q000378:metabolism*; D000693:Anaerobiosis; D004926:Escherichia coli / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D007773:Lactates / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D019802:Succinic Acid / Q000378:metabolism; D013997:Time Factors; D014462:Ultrafiltration
D000085:Acetates; D007773:Lactates; D000431:Ethanol; D019802:Succinic Acid; D010100:Oxygen