202 PRINCIPLES OF SOIL MICROBIOLOGY 



anaerobic conditions. They believed that the process is carried out by 

 the combined action of several organisms. Kroulik 30 used a medium, 

 similar to that employed by Omeliansky, consisting of 1 gram (NH 4 ) 3 P0 4 , 

 1 gram K 2 HP0 4 , 0.5 gram MgS0 4 , trace of NaCl, 1000 cc. distilled 

 water, 1 to 2 per cent cellulose and 0.5 to 1 per cent MgC0 3 . He demon- 

 strated the common occurrence of bacteria able to decompose cellulose 

 at 60° to 65°C, particularly in places where cellulose is present in abun- 

 dance. Both aerobic and anaerobic forms have been demonstrated. 

 Two aerobic forms were found in great abundance during the early stages 

 of decomposition, but when isolated on nutrient agar media, they did not 

 decompose cellulose further. Two anaerobic bacteria were isolated 

 which did not grow upon agar. 31 Various other thermophilic cellulose- 

 decomposing bacteria have also been isolated from the soil. 32 " -34 For this 

 purpose a medium consisting of 2 grams NaNH 4 HP0 4 H 2 0, 1 gram 

 KH 2 P0 4 , 0.3 gram CaCl 2 ,5grams peptone, 15 grams cellulose, 1000 cc. of 

 tap water and excess of CaC0 3 is inoculated with infusions of rapidly de- 

 composing manure and the cultures are incubated at 65°C. Gas bubbles 

 begin to rise after 18 to 24 hours and the formation of H 2 S becomes evi- 

 dent. 34 After 30 to 36 hours, the cellulose pulp is raised to the surface, 

 loses its fibrous structure, and turns brownish-yellow in color. Further 

 transfers do not form any more H 2 S. The cellulose begins to decompose 

 after 18 hours and the process is completed after 6 to 8 days. When 

 inoculations from individual colonies are made upon glucose agar, the 

 isolated cultures do not decompose cellulose. Pure cultures are ob- 

 tained by means of deep agar-cellulose tubes. The organism does not 

 grow at 28 to 37°C, makes some growth at 43° to 50°C, grows best 

 at 65°C. The spores are destroyed at 115° in 37 minutes. When 

 grown on common agar media, the power of cellulose decomposition is 

 lost. This is probably due to the loss of some highly oxidizable com- 

 ponent, during the process of plating, which is needed to initiate the 

 process of decomposition. 



A comparative summary of this thermophilic organism {Clostridium 



30 Kroulik, 1913 (p. 157). 



31 See also Noack, 1912 (p. 300). 



32 Pringsheim, H. tjber die Vergarung tier Zellulose durch thermophilc 

 Bakterien. Centrbl. Bakt. II, 38: 513-516. 1913. 



33 Langwell, H., and Lymn, A. Discussion on the action of bacteria on cellu- 

 losic materials. Jour. Soc. Chem. Ind. 42T: 280-287. 1923. 



34 Viljoen, J. A., Fred, E. B., and Peterson, W. H. The fermentation of cellu- 

 lose by thermophilic bacteria. Jour. Agr. Sci. 16: 1-17. 1926. 



