FAMILY VI. SIDEROCAPSACEAE 



227 



(Kungl. Svenska Vetenskapsakad. Handl., 

 62, 1922, 55.) 



li.ne.a'ris. L. adj. linearis linear. 



The type species of genus Siderobacter 

 Naumann. 



Cells 1.0 by 5.0 microns after the encrust- 

 ing iron compounds have been dissolved 

 away with dilute HCl. Opaque, encrusted 

 cells, 1.2 b}- 7.0 microns. Always occur 

 singl}' in contrast to the larger-celled 

 Siderobacter duplex, where the cells occur in 

 pairs. 



Source: Found in the Aneboda region in 

 Sweden. 



Habitat: Found in surface films and on 

 submerged objects. 



4. Siderobacter duplex Naumann, 1922. 

 (Kungl. Svenska Vetenskapsakad. Handl., 

 62, No. 4, 1922, 55.) 



du'plex. L. adj. duplex two-fold, double. 



Cells, 1.5 by 3.5 microns after encrusting 

 iron compounds are removed with dilute 

 HCl, occurring in pairs. 



Source: Found in the Aneboda region in 

 Sweden. 



Habitat: Found in surface films on the 

 water of swamps and small streams. 



5. Siderobacter latus Beger, 1941. 

 (Zent. f. Bakt., I Abt., Orig., 154, 1949, 63 

 and 66.) 



la'tus. L. adj. latus broad. 



Straight or occasionally curved cells, 2.5 

 b}^ 6.0 to 15.0 microns, usually occurring 

 singly. Participate in the formation of iron 

 and lime concretions. 



Source: Found on concretions on the 

 brick walls of two wells suppljang a rapid 

 sand filter near Berlin, Germany. 



Habitat : Found in the cool waters of deep 

 wells. 



Genus X. Ferrobacillus Leathen and Braley, 1954* 

 (Bact. Proc. 54th General Meeting, Soc. of Amer. Bact., 1954, 44.) 



Fer.ro. ba.cil'lus. L. noun /errum iron, here meaning ferrous iron; L. dim. noun bacillus 

 a small rod; M.L. noun Ferrobacillus ferrous-iron rodlet. 



Short, plump, rod-shaped cells occurring singly and in pairs, seldom in chains; the cells 

 are not united to form colonies. O.xidize ferrous iron to the ferric state in acid environments. 

 Optimum reaction, pH 3.5. 



The type species is Ferrobacillus ferrooxidans Leathen and Braley. 



1. Ferrobacillus ferrooxidans Leathen 

 and Braley, 1954. (Ferrous iron oxidizing 

 bacterium, Leathen, IMcIntyre and Braley, 

 Bact. Proc. 52nd General Meeting, Soc. of 

 Amer. Bact., 1952, 15; also see Leathen, 

 Braley and Mclntj're, Appl. Microbiol., 1, 



1953, 65; Leathen and Braley, Bact. Proc. 

 54th General Meeting, Soc. of Amer. Bact., 



1954, 44.) 



fer.ro.o'xi.dans. L. noun ferruni iron; 

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

 oxidize or make acid; M.L. part. adj. fer- 

 rooxidans iron-oxidizing. 



Rods 0.6 to 1.0 by 1.0 to 1.6 microns. 

 Motile, presumably polar flagellate. Gram- 

 negative. 



Ferrous iron-silica gel : Colonies are small 

 and raised with irregular margins. Young 

 colonies are glistening and tan, but gradu- 



ally become granular and brown with 

 oxidizing iron. A tan to brown area of 

 oxidized iron is frequently found around the 

 colony. 



Liquid ferrous iron medium (Leathen, 

 Mclntyre and Braley, Science, 114, 1951, 

 280): Rapidly oxidized; forms a precipitate 

 of ferric hydroxide or basic ferric sulfate. 



Acid thiosulfate liquid medium: Not 

 oxidized. 



Optimum reaction, pH 3.5. O.xidation 

 retarded below pH 2.2 and above pH 4.6. 



Optimum temperature, between 15° 

 and 20° C. 



Strictly autotrophic. Derives energy by 

 the o.xidation of ferrous iron to the ferric 

 state. Utilizes the CO2 of the atmosphere 

 as a source of carbon. 



Aerobic. 



*Description of genus and species prepared by Wm. W. Leathen, Mellon Institute, Pitts- 

 burgh, Pennsylvania. 



