204 PRINCIPLES OF SOIL MICROBIOLOGY 



comprises a variety of forms described under different names, including 

 Plectridium, 43 Clostridium 44 and Granulobacter. 45 However, not all 

 forms of Bac. amylobacter are capable of retting flax. Bac. felsineus 

 Carbone 46 is 3 to 5 by 0.3 to 0.4ju and forms free spores 3 by 1.5 to 2/x 

 in size. It is similar in morphology and general physiology to Bac. 

 amylobacter A. M. et Bred., but varies from the latter by being unable to 

 produce butyric acid. 40 



Bacteria decomposing hydrocarbons and benzene ring compounds. 

 Petroleum, paraffin oil and other hydrocarbons can be readily used by a 

 number of soil bacteria as sources of energy. 47 



To obtain an enriched culture, the following medium was used: 



Tap water 1000 cc. CaC0 3 trace 



K 2 HPO 4 0.5 gram One of the 



NH 4 C1 0.5 gram paraffins about 10.0 grams 



Petroleum, benzin and paraffin oil can be used directly. The paraffin is first 

 melted by warming and the solution is then vigorously shaken. The medium is 

 inoculated with soil and incubated. At 20°, fluorescent and fat-splitting organ- 

 isms develop; at 38°, Mycobacteria (4 to 10 by 0.5 to 1.5/x) and Micr. parajflnae 

 develop. Sohngen found that 4 to 8 mgm. of petroleum were oxidized in 24 hours 

 at 28°C. for every square centimeter of surface of solution. Pure cultures of the 

 organisms were obtained on a medium consisting of: 



Washed agar 20 grams Distilled water 1000 cc. 



K2HPO4 0.5 gram Paraffin vapor 



MgS0 4 0.5 gram 



The number of bacteria capable of oxidizing paraffin in the soil are very 

 large, reaching 50,000 to 200,000 per gram of garden soil. Among the 

 species isolated we find Bad. fluorescens liquefaciens and non-U quefaciens, 

 Bad. pyocyaneum, B. stutzeri. B. lipolyticum a, (3, 7 and 8, Micr. paraffinae, 

 and all fat-splitting forms. Tausz and Peter 48 isolated three organisms 

 from the soil capable of decomposing hydrocarbons: Bad. aliphaticum, 

 Bad. aliph. liquefaciens and Paraffi nbaderium . The first was isolated 



43 Winogradsky, S., and Friebes, V. Sur le rouissage du lin et son agent 

 microbien. Compt. Rend. Acad. Sci. 121: 242. 1895. 



44 Stormer, K. Ueber die Wasserroste des Flaches. Mitt. deut. Landw. 

 Gesell. 18: 193. 1903; Chem. Centrbl. 76: 41. 1905. 



45 Beijerinck and Van Delden, 1902 (p. 183). 



46 Carbone, D., and Tobler, F. Die RSste mit Bacillus felsineus. Faserforsch. 

 2: 163-184. 1923. 



47 Sohngen, N. L. Benzin, Petroleum, Paraffinol und Paraffin als Kohlen- 

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



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

 Hilfe von Bakterien. Centrbl. Bakt. II, 49: 497-554. 1919. 



