ISSN:
1432-072X
Keywords:
Key words Sulfide oxidation
;
Nitrate ammonification
;
Sulfur respiration
;
Sulfur reductase
;
Sulfurospirillum deleyianum
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Sulfurospirillum deleyianum grew in batch culture under anoxic conditions with sulfide (up to 5 mM) as electron donor, nitrate as electron acceptor, and acetate as carbon source. Nitrate was reduced to ammonia via nitrite, a quantitatively liberated intermediate. Four moles of sulfide were oxidized to elemental sulfur per mole nitrate converted to ammonia. The molar growth yield per mole sulfide consumed, Ym, was 1.5 ± 0.2 g mol–1 for the reduction of nitrate to ammonia. By this type of metabolism, S. deleyianum connected the biogeochemical cycles of sulfur and nitrogen. The sulfur reductase activity in S. deleyianum was inducible, as the activity depended on the presence of sulfide or elemental sulfur during cultivation with nitrate or fumarate as electron acceptor. Hydrogenase activity was always high, indicating that the enzyme is constitutively expressed. The ammonia-forming nitrite reductase was an inducible enzyme, expressed when cells were cultivated with nitrate, nitrite, or elemental sulfur, but repressed after cultivation with fumarate.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002030050252
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