Nitric oxide detoxification--a new era for bacterial globins in biotechnology?

For more than a decade, the expression of Vitreoscilla hemoglobin (VHb) has been used to improve the growth and/or productivity of various organisms that are important for the production of valuable metabolites and recombinant proteins by biotechnological processes. Extensive experimental data have shown that VHb enhances the energy status of the cell under oxygen-limited conditions, presumably by improving the supply of intracellular oxygen. Recently, bacterial globin proteins have gained more attention in research because of their ability to detoxify nitric oxide (NO) in vivo. These new results have increased our knowledge, encouraging us to reconsider the role of VHb in vivo. The expression of heterologous globins might improve cellular protection against nitrosative stress under oxygen-limited conditions.