FAMILY III. THIOBACTERIACEAE 



87 



1945. (Austral. Jour. Exper. Biol, and Med. 

 Sci., S3, 1945, 81; also see Jour. Gen. Micro- 

 biol., 8, 1953, 344.) 



con.cre.ti'vo.rus. L. noun concretum firm 

 or solid matter; L. v. voro to devour or de- 

 stroy; M.L. part. adj. co/ic?'e<iwrM.s concrete- 

 destroying. 



Short, straight rods 0.5 by 1.5 to 2.0 

 microns with square ends. Stain irregularly, 

 showing deeply stained granules in poorly 

 stained slender rods. Motile, presumably 

 polar flagellate. Motility lost in older cul- 

 tures. Single polar flagellum, two to three 

 times the length of the organism (unpub- 

 lished data). Gram-negative. 



Thiosulfate agar colonies: Minute, water- 

 clear, whitish yellow on prolonged incuba- 

 tion. No confluent growth. 



Thiosulfate liquid medium: Uniform tur- 

 bidit\-, slight deposit of sulfur. No pellicle. 



Sulfur liquid medium: Uniform turbidity; 

 floating sulfur granules fall to the bottom. 



Strictly aerobic. 



Temperature relations: Optimum, 28° C.; 

 slow growth at 10° and 37° C.; death occurs 

 at 55° C. 



Strictly autotrophic, utilizing atmos- 

 pheric CO2 as the source of carbon; growth 

 inhibited by higher concentrations of glu- 

 cose, glycerol and lactate. Derives energy 

 from its oxidation of elemental .sulfur, thio- 

 sulfate and hydrogen sulfide, o.xidizing 

 them ultimately to sulfate and sulfuric acid. 

 Thiosulfate is oxidized with the intermedi- 

 ate production of tetrathionate. 



Nitrogen sources: Utilizes ammonium- 

 and nitrate-nitrogen equally well. Nitrate 

 is not toxic whereas nitrite is. 



Optimum reaction: Growth occurs be- 

 tween pH 6.0 and acid concentrations up to 

 10 per cent. Sulfuric acid optimum is be- 

 tween pH 2.0 and 4.0. 



Distinctive characters: Responsible for 

 the rapid corrosion of concrete sewers and 

 other concrete structures where the sewer 

 air contains hydrogen sulfide. 



Habitat: Corroding concrete in sewers; 

 also found in sewage and presumably in soil 

 and fresh water. 



8. Thiobacillus thiooxidans Waksman 

 and Joffe, 1922. (Jour. Bact., 7, 1922, 239.) 



thi.o.ox'i.dans. Gr. noun thiuvi sulfur; 

 Gr. adj. oxys sharp, acid; M.L. v. oxido to 



make acid, to o.xidize; M.L. part. adj. thio- 

 oxidans oxidizing sulfur. 



Short rods: 0.5 by 1.0 micron with rounded 

 ends. Occur singly, in pairs or in chains. 

 Motile by means of a single polar flagellum. 

 Gram-negative (Starkey, Soil Sci., 39, 1935, 

 210). 



Thiosulfate agar: Scant growth. Nearly 

 transparent colonies. 



Sulfur broth: Uniform turbidity. No sedi- 

 ment or surface growth. Medium becomes 

 very acid (below pH 1.0). 



Thiosulfate broth: Uniform turbidity. 

 Medium becomes acid, and sulfur is precipi- 

 tated. 



Nitrogen sources: Utilizes ammonia- 

 nitrogen but not nitrate-nitrogen, which is 

 toxic. Asparagin, urea and peptone not 

 utilized. 



Temperature relations: Optimum, be- 

 tween 28° and 30° C. Slow growth at 18° 

 and 37° C. Death occurs between 55° and 

 60° C. 



Optimum reaction, between pH 2.0 and 

 3.5. (Limiting reactions, pH 6.0 to less than 

 pH 0.5.) 



Strictly autotrophic, deriving its energy 

 from the oxidation of elemental sulfur and 

 thiosulfate, o.xidizing these to sulfuric acid. 

 It utilizes the CO 2 of the atmosphere as a 

 source of carbon. 



Strictly aerobic. 



Distinctive characters: This species pro- 

 duces more acid, from oxidation of sulfur, 

 and continues to live in a more acid medium, 

 than any other living organism yet reported, 

 the hydrogen-ion concentration of the me- 

 dium increasing to a pH 0.6 and less. 



Source: Isolated from composts of soil, 

 sulfur and rock phosphate, and soils con- 

 taining incompletel}' oxidized sulfur com- 

 pounds. 



Habitat: Soil. 



9. Thiobacillus trautweinii Bergey et 

 al., 1925. (Thionsaurebakterium, Trautwein, 

 Cent. f. Bakt., II Abt., 53, 1921, 513; also 

 see ibid., 61, 1924, 1; Bergey et al.. Manual, 

 2nd ed., 1925, 39; Bacterium thiogenes 

 Lehmann, in Lehmann and Neumann, 

 Bakt. Diag., 7 Aufl., 2, 1927, 516.) 



traut.wein'i.i. M.L. gen. noun trautweinii 

 of Trautwein; named for K. Trautwein, who 

 first isolated and studied this species. 



