Expression of the gene encoding bacterial hemoglobin (VHb) from Vatreoscilla has been previously used to improve recombinant cell growth and enhance product formation under microaerobic conditions, a common phenomenon in large-scale cultivations of bacteria. This technology has now been applied to tobacco suspension cultures. Tobacco suspension cultures have been generated from VHb-expressing tobacco plants. Cell cultures were capable of producing an active hemoglobin. When grown in shake flasks, the cells did not show any lag-phase and exhibited improved cell growth, compared to controls carrying the parental plasmid.