DECOMPOSITION OF NON-NITROGENOUS ORGANIC MATTER 465 



tion than the fats; they are acted upon under completely aerobic 

 conditions by soil fungi and certain bacteria. It may be of interest to 

 mention here that Greig-Smith 117 attempted to explain soil exhaustion 

 as a result of an accumulation of fats and waxes ("agricere"); when 

 these are partly removed by the action of volatile antiseptics, further 

 decomposition of the soil organic matter sets in (see p. 759). 



Decomposition of paraffins, aliphatic hydrocarbons and benzene ring 

 compounds in the soil. According to Sohngen, 118 various non-spore 

 forming bacteria and Mycobacteria are capable of oxidizing paraffin, 

 benzin, petroleum and paraffin oil. On adding 2 grams of paraffin to 

 the medium, incubating one month at 28°, then extracting the remain- 

 ing paraffin with petroleum ether, it was found that the following 

 amounts were decomposed: 



mgm. 



Mycob. album 300 



Mycob. rubrum 330 



Micr. paraffinae 180 



Bad. fl<uorescens liquefaciens 180 



Crude culture 540 



In addition to the bacteria, certain fungi are also capable of utiliz- 

 ing paraffins as sources of energy. Tausson 119 found that Asp. flavus 

 decomposed paraffin of a high melting point (+78°), with an economic 

 coefficient of 53 to 66.5 per cent. A white Penicillium has been found 120 

 to be capable of using paraffin as the only source of energy. 



Bad. aliphaticum isolated from the soil is capable of decomposing 

 quantitatively benzol, n-hexan (CH 3 (CH 2 )4CH 3 ), n-octan (CH 3 (CH 2 ) 6 - 

 CH 8 ), (di-iso-amyl ((CH 3 ) 2 CH(CH 2 ) 4 -CH(CH 3 ) 2 ), n-hexadecan (CH 3 - 

 (CH 2 )i 4 CH 3 ), triocontan (C 30 H 62 ) and tetratriocontan (C 34 H 7 o), but not 

 naphthenes. 121 Bad. aliphaticum liquefaciens decomposes small quanti- 

 ties of naphthenes; the physical constants of the corresponding hydro- 

 carbon change thereby giving higher values. The organism can be 

 used for testing the purity of naphthene hydrocarbons and for the 

 separation of aliphatic hydrocarbons from naphthenes, since the former 

 are decomposed quantitatively. 



117 Greig-Smith, 1912 (p. 760). 



118 Sohngen, N. L. Benzin, Petroleum, Paraffinol und Paraffin als Kohlenstoff- 

 und Energiequelle fur Mikroben. Centrbl. Bakt. II, 37: 595-609. 1913. 



119 Tausson, W. O. Zur Frage iiber Assimilation des Paraffins durch Mikro- 

 organismen. Biochem. Ztschr., 166: 356-368. 1925. 



120 Rahn, O. Ein Paraffin zersetzender Schimmelpilz. Centrbl. Bakt., 16: 

 382-384. 1906. 



»» Tausz and Peter, 1920 (p. 408). 



