[5] When the gene (vgb) for this haemoglobin was cloned into E. coli[6] it was found that it increased the growth of these cells under low oxygen conditions compared to control bacteria.
[7] The concentration of VHb drastically increased in Vitreoscilla, a strict aerobe, grown under hypoxic conditions,[8] and it was proposed that it acted as an "oxygen storage trap" to feed oxygen to the terminal oxidase (cytochrome bo) under these conditions.
Its main role is likely the binding of oxygen at low concentrations and its direct delivery to the terminal respiratory oxidase(s) such as cytochrome o.
[15] Since it was shown that VHb stimulated the growth of E. coli under hypoxic conditions, vgb was cloned into a variety of organisms, including various bacteria, yeast, fungi, and even higher plants and animals to test its effects on growth and production of products of potential commercial importance, the degradation of toxic compounds, the enhancement of nitrification in wastewater treatment, and other environmental applications.
Other environmental investigations include those related to heavy metal remediation and provision of soil phosphate to plants.
[31] Furthermore, it was shown that the mechanism of haeme protein expression to enhance oxygen supply to the monooxygenase in nitrification under hypoxic conditions is similar to VHb function seen in other applications.