Correlation between bacterial hemoglobin and carbon sources: their effect on copper uptake by transformed E. coli strain alpha DH5.

Escherichia coli alphaDH5 harboring Vitreoscilla hemoglobin gene, vgb (Escherichia:pUC8:16), and control strains (parental and vgb-lacking transformed strains, E. coli:pUC9) were employed for studying the potential ability of copper uptake. The strains were grown on a minimal medium, 5XM9, that contained different carbon (mannitol, fructose, lactose, and maltose) and nitrogen (casein and yeast extract) sources. A clear type-response relationship between the level of copper uptake and the type of carbon and nitrogen sources was observed. Copper uptake ability was better for vgb-bearing cells grown on either mannitol, lactose, fructose, or maltose as carbon source and casein as well as yeast extract as nitrogen source compared with the control medium. The increase in copper uptake was in the following order: parental cells, then pUC9-bearing cells, then VHb-expressing cells.