Is it fermentation?

[druid]

There are sulfate reducing bactria which use sulfur disproportionation
reaction:
S2O3 + H2O -> SO4 + H2S

Is this process called fermentation? (no outside e-acceptor ( by definition of
disproportionation redox reaction ))

[MrMistery]

no it ain't fermentation. the bacteria use the energy from that reaction to make their carbon coumponds. then they may use regular cellular respiration or fermentation to break them down..

[druid]

no it ain't fermentation. the bacteria use the energy from that reaction to make their carbon coumponds. then they may use regular cellular respiration or fermentation to break them down..

One definition says fermentation is a reaction with no external e-acceptor. The permutation reaction is a such reaction. You say that's not fermentation. Thus, the above definition is incorrect. So what is fermentation? Give please the exact definition.