Vila P, Corchero J L, Benito A, Villaverde A
Institut de Biologia Fonamental, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Biotechnol Prog. 1994 Nov-Dec;10(6):648-51. doi: 10.1021/bp00030a010.
The effect of ammonium as a medium supplement on plasmid-encoded recombinant beta-galactosidase synthesis was explored in Escherichia coli cells during aerobic growth in complex medium. After induction, only doses of ammonium chloride below 1 g/L are able to transiently enhance the yield. However, the presence of nontoxic ammonium chloride concentrations of up to 10 g/L results in lower values of beta-galactosidase in a concentration-dependent fashion. A significant reduction in plasmid DNA content explains the decrease in the yield by a gene-dosage-involving mechanism.
