The hemoglobin from the bacterium Vitreoscilla(VHb) is the firstmicrobial hemoglobin, which has been extensively studied with respect to its structure, biochemical functions, and the mechanisms by which itsexpression is controlled. Expressing VHb in a variety of heterologous hostsresults substantial increasesin production of a variety of useful products(antibiotics, proteins, polymersetc.), host resistance andability to degrade some harmful compounds, by promoting oxygen transport to enhance respiratory and...