DECOMPOSITION OF NON-NITROGENOUS ORGANIC MATTER 441 



Oidium lactis and Bac. calfactor were found capable of heating up 

 well packed hay and a mixture of two of these organisms could bring 

 about a normal heating of moist hay. In addition to these, Miehe 42 

 isolated an actinomyces and various fungi from the piles of heated 

 hay. However, the actual role of these organisms in the heating 

 of hay is still unclear. It has been suggested that either inflam- 

 mable products are formed or that the initial reaction of raising the 

 temperature is biological, followed by chemical processes. 



Decomposition of cellulose by denitrifying bacteria. In the decom- 

 position of cellulose by denitrifying bacteria, the energy liberated is 

 used for the reduction of nitrates to atmospheric nitrogen; the oxygen 

 thus obtained is utilized for the oxidation of the cellulose. Carbon 

 dioxide and water are the chief products formed in the decomposition 

 of cellulose, while nitrogen gas is a product of the reduction of nitrates. 

 The formation of carbonates, due to the reduction of the nitrates, 

 leads to the alkalinization of the medium: 



5 C«H 1() 6 + 24 KN0 3 = 24 KHC0 3 + 12 N 2 + 6 C0 2 + 13 H 2 

 C 6 Hio0 5 + 8 KNO3 = 4 KHCO3 + 2 K2CO3 + 4 N 2 + 3 H 2 



Groenewege 43 demonstrated that this process of cellulose decom- 

 position is a result of the symbiotic action of two groups of bacteria, 

 one of which decomposes the cellulose and the other reduces the nitrate 

 utilizing the energy liberated by the former. By the combination of 

 these two processes the cellulose is decomposed much more readily 

 than by the cellulose bacteria alone. Under aerobic conditions, cellu- 

 lose decomposition takes place readily with other sources of nitrogen, 

 as seen from table 35. 



The cellulose decomposing organism produces an enzyme which 

 hydrolyzes the cellulose into sugars. The latter are transformed by 

 the organism into organic acids (acetic, butyric and lactic). The 

 sugars and the acids are used as sources of energy by the denitrifying 

 bacteria which decompose them into C0 2 and water. The intermediary 

 products of cellulose decomposition can also be used as a source of 

 energy by Az. chroococcum which is enabled thereby to fix nitrogen 

 and form dark brown pigments in the soil. 



Cellulose decomposition by actinomyces. The capacity of decomposing 

 cellulose and using it as a source of energy is well distributed among 

 the actinomyces. 44 This can be readily demonstrated either by the 



43 Groenewege, 1920-1923 (p. 436). 



44 Fousek, 1913 (p. 302). 



