Escherichia coli growth and plasmid copy numbers in continuous cultivations

Pekka Reinikainen, Ilkka Virkajärvi

Research output: Contribution to journalArticleScientificpeer-review

30 Citations (Scopus)


AnEscherichia coli K-12 strain harbouring either the plasmid pBR322, or the recombinant plasmid pKTH1220, a 14 kb derivative of pBR322, or no plasmid was grown in a chemostat. The cultivations were continued for 300–400 bacterial generations.E. coli hosts harbouring pBR322 or no plasmid grew in a similar way, but the growth of the host containing the big recombinant plasmid was slower.
The plasmid copy numbers increased up to 2–3 fold as the dilution rate was increased from 0 to ca. 1 h−1. After this point the increase in dilution rate seemed to induce a rapid decrease in the plasmid copy numbers.
High copy numbers could be maintained using dilution rates resulting in good productivity of the cell mass.
Original languageEnglish
Pages (from-to)225-230
JournalBiotechnology Letters
Issue number4
Publication statusPublished - 1989
MoE publication typeA1 Journal article-refereed


  • Escherichia coli

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