title: Effect of oxygen supply on metabolism of immobilized and suspended Escherichia coli.
abstract: The effect of reduced oxygen supply on the production of a recombinant protein (plasmid-encoded beta-galactosidase) was investigated in Escherichia coli. A novel modified bubble tank reactor was used to provide a direct comparison between immobilized and suspended cells in identical environments except for the immobilization matrix. Decreased oxygen supply led to increased beta-galactosidase synthesis by both immobilized and suspended cells. Immobilized cells produced similar amounts of beta-galactosidase as the suspended cells. Lactose consumption and acetate production, on a per cell basis, were significantly higher in immobilized cells, suggesting that immobilized cells utilized fermentative metabolism. However, a transport analysis of the immobilized cell system showed that immobilized cells were not subject to either external or internal mass transfer gradients.
authors.affiliation: Department of Molecular Biology and Genetics, Bilkent University, 06533 Bilkent, Ankara, Turkey.
authors.forename: E
authors.initials: E
authors.lastname: Inanç
authors.forename: J E
authors.initials: JE
authors.lastname: Miller
authors.forename: D
authors.initials: D
authors.lastname: Dibiasio