Recent advances in understanding the structure, function, and biotechnological usefulness of the hemoglobin from the bacterium Vitreoscilla

Abstract

The hemoglobin from the bacterium Vitreoscilla (VHb) is the first microbial hemoglobin that was conclusively identified as such (in 1986). It has been extensively studied with respect to its ligand binding properties and mechanisms, structure, biochemical functions, and the mechanisms by which its expression is controlled. In addition, cloning of its gene (vgb) into a variety of heterologous hosts has proved that its expression results substantial increases in production of a variety of useful products and ability to degrade potentially harmful compounds. Recent studies (since 2005) have added significant knowledge to all of these areas and shown the broad range of biotechnological applications in which VHb can have a positive effect.

Effects of Citrobacter freundii ATP Production and Oxygen Intake Two Different Plasmids Carrying the Vitreoscilla Hemoglobin Gene (vgb)

“…It is known that recombinant (plasmid carrying) bacterial cells have a growth disadvantage, require more oxygen (due to perturbations in cellular metabolism) then grow disproportionately poorly under oxygen-limited conditions compared with plasmid-free cells (Erenler et al, 2004). The major function of VHb was the binding of oxygen and increasing ATP production under hypoxic conditions (Stark et al, 2011). We repot here expression of VHb and its effect on ATP production, oxygen uptake and cell mass of pMK79 and pUC8:15 from Citrobacter freundii.…”

Effective ethanol production from whey powder through immobilizedE. coliexpressingVitreoscillahemoglobin

“…[47][48][49] Further engineering of strain FBR5 to express the hemoglobin (VHb) from the bacterium Vitreoscilla (strain TS3) has been shown to improve its growth and ethanol production capabilities. [50][51][52] This is one application of a much more general use of engineering with VHb to enhance microbial growth and productivity. 53,54,[50][51][52] Strains FBR5 and TS3 have been compared regarding ethanol production from a variety of substrates, including pure sugars or corn stover; 55,56 potato processing waste; 3 sugar beet molasses, whey, and whey powder; 4 and mixed waste containing corn lignocellulose and potato starch.…”

Repeated batch fermentation of immobilizedE. coliexpressingVitreoscillahemoglobin for long-term use

“…[23][24][25] Bacterial hemoglobin (Vitreoscilla hemoglobin, VHb) is an effective tool for engineering of microorganisms for enhancement of growth and productivity. 26,28 Enhancement of ethanol production was achieved by expressing VHb in strain FBR5 (producing strain TS3). 29,30 Strains FBR5 and TS3 have been compared for their ethanol production efficiencies using different carbon sources including pure sugars and maize stover, 29,30 potato processing waste water, 31 sugar beet molasses, whey and whey powder, 32 and maize and potato processing waste.…”