Reduction of inorganic sulphur compounds by facultatively aerobic bacteria

Abstract

SUMMARYAmongst the family of the Enterobacteriaceae the ability to reduce tetrathionate to thiosulfate and thiosulfate to sulfite and sulfide occurs in the genera Proteus, Citrobacter and Salmonella. These reductions are coupled to a respiratory chain which functions under anaerobic conditions. Only during transport of electrons to tetrathionate oxidative phosphorylation has been demonstrated.Isolation and purification of the cytoplasmic membrane bound tetrathiohate and thiosulfate reductase from Proteus mirabilis makes clear that this bacterium forms only one enzyme for both reductions. This enzyme has a molecular weight of 133,000 daltons and can be divided into two subunits with molecular weights of 43,000 and 90,000 daltons by treatment with sodium dodecyl sulfate and 2-mercaptoethanol.The reduction of tetrathionate is activated by its primary product thiosulfate.Nitrate or oxygen represses and inactivates the tetrathionate and thiosulfate reductase. Nevertheless the smaller subunit of this enzyme appears to be formed and assembled into the cytoplasmic membranes after anaerobic growth in the presence of nitrate. EXPERIMENTAL Regulation o/the/ormation o/tetrathionate and thiosul/ate reductaseAmongst the family of the Enterobacteriaceae members of the genera Proteus, Citrobacter and Salmonella exhibit the ability to reduce tetrathionate to thiosulfate, and thiosulfate to sulfite and sulfide. The concerning specific enzyme activities for three representatives of these genera are listed in Table 1. The enzyme activities

The possible role of thiosulfate in the precipitation of 34S-rich barite in some Mississippi Valley-type deposits

“…Some species of bacteria are capable of metabolizing only the sulfur in the sulfane site; some utilize the sulfane and sulfonate atoms sequentially. Other strains perform a dissimilatory reduction in which hydrogen sulfide and sulfite are produced (Oltmann et al 1975). Sulfite generated by dissimilatory reduction may be reduced to sulfide by certain bacteria, oxidized to sulfate, or combined with hydrogen sulfide by inorganic processes to form thiosulfate (Chambers and Trudinger 1979a).…”

The phs gene and hydrogen sulfide production by Salmonella typhimurium

“…On the other hand, H2S production from thiosulfate by other members of the family Enterobacteriaceae, namely Proteus mirabilis and Citrobacterfreundii, has been suggested to be a relatively unimportant secondary activity of the anaerobic respiratory enzyme that reduces tetrathionate to thiosulfate (15,25,26). S. typhimurium is also capable of tetrathionate reduction (7,26), but even less is known about this anaerobic activity in Salmonella spp. except that tetrathionate reductase is also a molybdoenzyme (12).…”

Autotrophic, mixotrophic and heterotrophic growth with denitrification by Thiobacillus A2 under anaerobic conditions

“…The growth yield of 275 mg/l from 1.54 mM glucose (Y = 66.4 g/mol) and 42.3 mM formate (Y = 3.2 g/tool) is probably consistent with that calculated for glucose + formate separately: 102+ 135 =237 mg/1. This suggests that energy conservation anaerobically is about two-thirds of the aerobic value, which is typical of bacteria growing on nitrate rather than oxygen [15,16] and indicates an aerobic: anaerobic phosphorylation ratio of 3 : 2 [17][18][19]. The growth yields of Thiobacillus A2 on glucose of 66.4 (nitrate) and 68.6 (N20) in the chemostat can be compared to aerobic yields of 107-115 g/mol [2,9,10].…”