1 research outputs found
Independence of Nitrate and Nitrite Inhibition of <i>Desulfovibrio vulgaris</i> Hildenborough and Use of Nitrite as a Substrate for Growth
Sulfate-reducing microbes, such as Desulfovibrio
vulgaris Hildenborough, cause “souring”
of petroleum reservoirs through produced sulfide and precipitate heavy
metals, either as sulfides or by alteration of the metal reduction
state. Thus, inhibitors of these microbes, including nitrate and nitrite
ions, are studied in order to limit their impact. Nitrite is a potent
inhibitor of sulfate reducers, and it has been suggested that nitrate
does not inhibit these microbes directly but by reduction to nitrite,
which serves as the ultimate inhibitor. Here we provide evidence that
nitrate inhibition of D. vulgaris can
be independent of nitrite production. We also show that D. vulgaris can use nitrite as a nitrogen source
or terminal electron acceptor for growth. Moreover, we report that
use of nitrite as a terminal electron acceptor requires nitrite reductase
(<i>nrfA</i>) as a D. vulgaris <i>nrfA</i> mutant cannot respire nitrite but remains
capable of utilizing nitrite as a nitrogen source. These results illuminate
previously uncharacterized metabolic abilities of D.
vulgaris that may allow niche expansion in low-sulfate
environments. Understanding these abilities may lead to better control
of sulfate-reducing bacteria in industrial settings and more accurate
prediction of their interactions in the environment