does thiobacillus denitrificans produce acid?

Lesley Robertson l.a.robertson at
Thu Dec 10 05:03:23 EST 1998

Rico Coolen wrote:

> High Group Michael,
> I do not know if it does but would not nitric acid be more logic. From
> nitrate NO4- tot S03- - is a long way to go.

I'm afraid that you don't understand what is going on here. Thiobacillus
denitrificans is an obligate autotroph that gets its energy for growth by
oxidizing sulphide or thiosulphate. If it uses oxygen as electron
acceptor, every mol of reduced sulphut compound is converted into a mol of
sulphuric acid. If it uses nitrate (NO3- by the way), sulphate (SO4=) is
produced, together with some sulphuric acid (H2SO4). Anyone interested in
more info could consult basic microbiology texts (Schelegel? Brock?), the
Prokaryotes, or Berget's Manual, but the redox balances are simple enough
to work out.
Lesley Robertson

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