Vanadate electron acceptor

Carpentier W, L De Smet, J Van Beeuman, A Brige (2005) Respiration and growth of Shewanella oneidensis MR-1 using vanadate as the sole electron acceptor. J Bacterial 187 3293-3301. 

Vanadium minerals are essentially formed in the course of geological processes. An epigenic formation of specific minerals is, however, conceivable certain bacteria, such as Pseudomonas vanadiumreductans and Shewanella oneidensis (Figure 1.3), can use vanadate(V) as an external electron acceptor, reducing vanadate(V) to vanadium(IV) [and perhaps even further to vanadium(III)], and thus producing sherwoodite-like inorganic... 

The idea of vanadate (and vanadyl, the first reduction product of vanadium after vanadate had entered the ascidian) acting as electron acceptors is an attractive view in the light of vanadate actually being a primary electron acceptor for the bacterium Shewanella oneidensis (Section 4.5). 

Although the question of whether or not vanadium-dependent nitrate reductases actually exist has still to be settled, the ability of bacteria to use vanadate(V) as a primary electron acceptor is well established by now and will be addressed in the next section. 

S. oneidensis cells pre-grown on fumarate exhibit a pronounced ability to use vanadate as an electron acceptor. Formate and, in particular, lactate are employed as electron sources. Under optimal conditions, ca 16 mM of vanadate is reduced per gram of bacteria per hour, with a biomass doubling time of 10( 1) the absolute yield being... 

Vanabins, storage proteins for the vanadyl cation found in ascidians, and containing up to 20 VO + attached to amine terminals of lysines (section 4.1.2 and Figure 4.4). A vanadium(IV)-binding protein was also isolated from the bacterium Pseudomonas isachenkovii (Section 4.5) which utilises vanadate as terminal electron acceptor in anaerobic respiration, and appears as well to be present in the hydrogen bacterium Xanthobacter autotrophicus. ... 

Vanadate can probably be reduced to a less toxic form in the cytoplasm (Capella et al. 2002), so that oxidation states other than + 5 [e.g., V(IV) or V(III)] may also be present (Michibata et al. 2002, Nagaoka et al. 2002). As it can be reduced under biological conditions, vanadate also serves as electron acceptor for anaerobic respirations (Yurkova... 

---