250 ORDER I. PSEUDOMONADALES 



Genus III. Methanobacterium Kluyver and van Niel, 1936* 

 (Zent. f. Bakt., II Abt., 94, 1936, 399.) 



Me.tha.no.bac.te'ri.um. Gr. noun iiiethy wine; M.L. noun methanum methane; Gr. 

 neut.n. bacterium a small rod; M.L. noun Methanobacterium the methane (-producing) 

 rodlet. 



Straight or slightly curved rods, sometimes united in bundles or long chains. Reported to 

 be non-motile. Anaerobic. Chemo-heterotrophic or chemo-autotrophic, oxidizing various 

 organic or inorganic compounds and reducing carbon dioxide to methane. Gram-negative. 



The anaerobic genus Methanobacterium was proposed by Kluyver and van Niel in 1936 with 

 an indication that they regarded Sohngen's methane bacterium as the type species of the 

 genus. Later, Barker (1936) found organisms that he regarded as identical with those pre- 

 viously isolated by Sohngen, and he proposed the name Methanobacterium sohngenii for this 

 species. While the organisms belonging to this genus are reported to be non-motile, the 

 curved form of their cells and their physiology places them near the species placed in De- 

 suFovibr-io. 



The type species is Methanobacterium soehngenii Barker. 



1. Methanobacterium soehngenii Acetate and n-butyrate but not pro- 

 Barker, 1936. (Methane bacterium, Sohn- pionate are fermented with the production 

 gen, Dissertation, Delft, 1906; Barker, Arch. of methane and carbon dioxide, 

 f. Mikrobiol., 7, 1936, 433.) Ethyl and n-butyl alcohols not fermented. 



soehn.ge'ni.i. M.L. gen.noun soehngenii Obligate anaerobe, 



of Sohngen; named for Prof. N. L. Sohngen, g^^^.^^ . Enrichment cultures containing 



the bacteriologist who first studied this acetate or butyrate as the only organic com- 



?,,■., ,. , , , , pound. Four strains were isolated from ace- 

 Rods straight to slightly curved, moder- "■' . . ^ ,^ rr,, ,., 

 ^ , , ,, ,., ^, ,. tate enrichment cultures. The cultures were 

 ately long. ISon-motile. Gram-negative. .^ , , . , 



In liquid cultures, cells are character- highly purified but not strictly pure, 

 istically joined into long chains which often Habitat: Canal mud, sewage. Probably 



lie parallel to one another so as to form occurs widely in fresh-water sediments 



bundles. where anaerobic conditions prevail. 



Genus IV. Cellvibrio Winogradsky, 1929.] 

 (Ann. Inst. Pasteur, J^S, 1929, 577.) 



Cell.vib'ri.o. L. noun cella a room, cell; L. v. vibro to vibrate; M.L. mas.n. Vibrio that 

 which vibrates, a generic name; M.L. mas.n. Cellvibrio cell vibrio, but here the cell is an 

 abbreviation of cellulose, hence, cellulose vibrio. 



Long slender rods, slightly curved, with rounded ends, showing deeply staining granules 

 which appear to be concerned in reproduction. Monotrichous. Most species produce a yellow 

 or brown pigment with cellulose. Oxidize cellulose, forming oxycellulose. Growth on ordi- 

 nary culture media is feeble. Found in soil. 



The type species is Cellvibrio ochraceus Winogradsky. 



Key to the species of genus Cellvibrio. 



I. No growth on glucose or starch agar. 



A. Ochre-yellow pigment produced on filter paper. 



1. Cellvibrio ochraceus. 



* Revised by Prof. Robert S. Breed, Cornell University, Geneva, New York, May, 1955. 

 t Revised by Prof. Robert S. Breed, Cornell University, Geneva, New York, with the 

 assistance of Prof. Onorato Verona, University of Pisa, Pisa, Italy, September, 1953. 



