372
CLAUDE FROMAGEOT AND JACQUES C. SENEZ
pH and stops growing when the pH drops below 5.0 (86). At the other
end of the scale there are strains of T. thiooxidans and T. ferrooxidans
which grow only at pH levels below 5.0 and which can develop at zero
or even at negative pH values (87). Many intermediate forms also exist.
TABLE VIIJ
THE PRINCIPAL MEMBERS OF THE BACTERIAL GENUS Thiobacillus
Organism
T. thioparus
T. denitrificans
T. thiooxidans
T. ferrooxidans
T. thiocyanooxidans
T. novellus
Optimum pH
approx. 7.0
approx. 7.0
5.0
5.0
7.0
7.0
Remarks
Type species
Facultative anaerobe; able to grow
anaerobically on media containing nitrate which is reduced to N 2
Elementary sulfur is rapidly oxidized; at the end of incubation,
pH in the cultures can be lowered
to 0 or even to negative values
Very similar to T. thiooxidans, with
the difference that elementary S
is slowly oxidized and that sulfur
compounds can be replaced as
energy source by the oxidation of
ferrous to ferric iron
Thiocyanate can be utilized as sole
source of energy, carbon, and
nitrogen
Facultative autotroph; can grow on
organic media in the absence of
inorganic sulfur compounds
References
0
(a,b)
(b)
(c)
(d)
(e)
(/)
a REFERENCES: (a) A. Nathanson, Mitt. zool. Station Neapel 15, 655 (1902); (5) M. W.
Beijerinck, Centr. Bakteriol. 11/11, 593 (1904); (c) S. A. Waksman and J. S. Joffe, Science
53, 216 (1921); (d) A. R. Colmer, K. L. Temple, and M< E. Hinkle, /. Bacteriol. 59, 317
(1950); (e) F. C. Happold and A. Key, Biochem. J. 31, 1323 (1937); (/) R. L. Starkey,
Soil. Sei. 39, 197 (1935).
The thiobacilli are strict aerobes, with the single exception of the
facultative anaerobe T. denitrificans. The metabolism of this species is
identical with that of T. thioparus in aerobiosis, but it can also grow in
the absence of free oxygen if the medium contains nitrate, which is
reduced to gaseous nitrogen:
3S 2 0 3
2 - + 5NO3- = fN 2 + 6SO4
2 -
(-AF° 298 o = +549 kcal.)
It should be emphasized that nitrate is utilized only for the oxidation of the sulfur-containing substrate and is not assimilated. For T.
CLAUDE FROMAGEOT AND JACQUES C. SENEZ
pH and stops growing when the pH drops below 5.0 (86). At the other
end of the scale there are strains of T. thiooxidans and T. ferrooxidans
which grow only at pH levels below 5.0 and which can develop at zero
or even at negative pH values (87). Many intermediate forms also exist.
TABLE VIIJ
THE PRINCIPAL MEMBERS OF THE BACTERIAL GENUS Thiobacillus
Organism
T. thioparus
T. denitrificans
T. thiooxidans
T. ferrooxidans
T. thiocyanooxidans
T. novellus
Optimum pH
approx. 7.0
approx. 7.0
5.0
5.0
7.0
7.0
Remarks
Type species
Facultative anaerobe; able to grow
anaerobically on media containing nitrate which is reduced to N 2
Elementary sulfur is rapidly oxidized; at the end of incubation,
pH in the cultures can be lowered
to 0 or even to negative values
Very similar to T. thiooxidans, with
the difference that elementary S
is slowly oxidized and that sulfur
compounds can be replaced as
energy source by the oxidation of
ferrous to ferric iron
Thiocyanate can be utilized as sole
source of energy, carbon, and
nitrogen
Facultative autotroph; can grow on
organic media in the absence of
inorganic sulfur compounds
References
0
(a,b)
(b)
(c)
(d)
(e)
(/)
a REFERENCES: (a) A. Nathanson, Mitt. zool. Station Neapel 15, 655 (1902); (5) M. W.
Beijerinck, Centr. Bakteriol. 11/11, 593 (1904); (c) S. A. Waksman and J. S. Joffe, Science
53, 216 (1921); (d) A. R. Colmer, K. L. Temple, and M< E. Hinkle, /. Bacteriol. 59, 317
(1950); (e) F. C. Happold and A. Key, Biochem. J. 31, 1323 (1937); (/) R. L. Starkey,
Soil. Sei. 39, 197 (1935).
The thiobacilli are strict aerobes, with the single exception of the
facultative anaerobe T. denitrificans. The metabolism of this species is
identical with that of T. thioparus in aerobiosis, but it can also grow in
the absence of free oxygen if the medium contains nitrate, which is
reduced to gaseous nitrogen:
3S 2 0 3
2 - + 5NO3- = fN 2 + 6SO4
2 -
(-AF° 298 o = +549 kcal.)
It should be emphasized that nitrate is utilized only for the oxidation of the sulfur-containing substrate and is not assimilated. For T.