AUTOTROPHIC BACTERIA 97 



The medium used by Sohngen consisted of: 



Distilled water 1000 cc. 



K0HPO4 0.05 gram 



MgNH 4 PO i -6H 2 0.1 gram 



CaS0 4 0.01 gram 



Inoculation was made with soil. The atmosphere consisted of one part CH 4 



and two parts air. 94 



Certain other common bacteria are capable of oxidizing methane, as 

 in the case of Bad. pyocyaneum 95 and Bad. fluorescens liquefaciens. 96 

 Miinz 97 isolated a methane oxidizing organism, not identical with that 

 of Sohngen, which he also called Methanomonas methanica. It thrives 

 at 18° to 40° with an optimum at 34°C. This organism measured 0.9 to 

 2.2 by 0.3 to 0.4/x in size, was elliptical to cylindrical, non-motile. High 

 methane and low oxygen content of atmosphere were best for its 

 growth, although the organism was aerobic. Hydrogen and carbon 

 monoxide could not replace methane, although alcohols, carbohydrates 

 and salts of organic acids could. Nitrogen was utilized both in in- 

 organic and organic forms. The organism may be considered as 

 facultative autotrophic although the autotrophy of this organism is 

 still questionable. 



B. hexacarbovorum was found 98 to be able to utilize methane, toluol, 

 xylol and illuminating gas as the only sources of carbon. Various other 

 hydrocarbons can also be utilized as sources of energy by bacteria. 99 

 In this connection mention should be made of the work of Sohngen on 

 the Mycobacteria {M. ladicola, M. phlei), which were found capable of 

 deriving their energy from the oxidation of benzol, paraffin, petroleum, 

 and assimilating the C0 2 of the atmosphere. In regard to the oxidation 



. 94 Kaserer, H. liber die Oxydation des Wasserstoffes und des Methans durch 

 Mikroorganismen. Centrbl. Bakt. II, 15: 573-576. 1906. 



95 Sohngen, N. L. Het onstaan en verdwijnen van Waterstof en Methaan 

 onder den invloed van het organische leven. Proefschrift. Delft. 1906 (Bot. 

 Centrbl. 105: 371-372. 1907.) 



96 Aiyer, P. A. S. The gases of swamp rice soils. V. A methane-oxidizing 

 bacterium from rice soils. Mem. Dept. Agr. India, Chem. Ser. 5: 177 180. 1920. 



97 Miinz, E. Zur Physiologie der Methanbakterien. Diss. Halle, 1915. 

 98 Stormer, 1907 (p. 47). 



99 Tausz, J., and Peter, M. Neue Methode der Kohlenwasserstoffanalyse mit 

 Hilfe von Bakterien. Centrbl. Bakt. II, 49: 497-554. 1920. 



