The Reverse electron
transport/flow is a mechanism in microbial metabolism in
which Chemolithotrophs using an electron donor with a higher redox
potential than NAD(P)+/NAD(P)H, such as nitrite or sulfur
compounds, must use energy to reduce NAD(P)+.
So this will provide specific
nutrient based niche for microbes because this method require more
energy for survival so such microbes are completly depend on
perticular noche of having reverse electron flow.
This energy is supplied by
consuming proton motive force to drive electrons in a reverse
direction through an electron transport chain.
Sometimes, the energy consumed in
reverse electron transport is five times greater than energy gained
from the forward process in metabolism.
So some Autotrophs can use this
process to supply reducing power for inorganic carbon
fixation.