DECOMPOSITION OF NON-NITROGENOUS ORGANIC MATTER 433 



acetaldehyde, methane and carbon dioxide. The last two were in the ratio of 

 1:7.2 at the beginning of the experiment and 1:3.4 at the close. In another set 

 of experiments, an alkaline medium was used; the same qualitative but different 

 quantitative results were obtained, there being a large amount of hydrogen 

 evolved in the alkaline medium. 



Hoppe-Seyler 20 placed 25.773 grams of filter paper into 1000 cc. flasks 

 containing 700 cc. of water; this was inoculated with sewage and 

 the gaseous products collected over mercury. The cultures were incu- 

 bated at room temperature for four years. During the first year there 

 was considerable gas evolved, but the evolution gradually became 

 slower until, at the end of four years, the evolution of gas had practically 

 ceased. The analysis showed that 15 grams of the cellulose had been 

 decomposed with the formation of carbon dioxide and methane. 

 Hoppe-Seyler was unable to find any of the true sugars, although he 

 thought it possible that there were some dextrin compounds in solu- 

 tion. When air was excluded, there was a greater production of me- 

 thane and to a less extent carbon dioxide. Hoppe-Seyler suggested 

 that the process of cellulose decomposition proceeds in two stages: 

 the cellulose is first hydrated with the formation of glucose, ac- 

 cording to the equation : 



(C 6 H 10 O 5 )„ + nH 2 = nC 6 H, 2 6 



The glucose is then broken down to carbon dioxide and methane: 



C 6 H 12 6 = 3C 2 H 4 2 = 3C0 2 4- 3CH 4 



This reaction depended on the supply of oxygen; the greater the amount 

 of available oxygen the less CH 4 and the more C0 2 was formed in the 

 process. However, neither was glucose demonstrated as an inter- 

 mediary product nor was there any evidence submitted that only 

 C0 2 and CH 4 are formed. 



Omeliansky 21 distinguished methane and hydrogen fermentations of 

 cellulose, both processes being anaerobic in nature; organic acids, 

 alcohols and gases were also formed. Van Iterson 22 was the first to 

 demonstrate that cellulose decomposition may also take place under 

 aerobic conditions. Aerobic and anaerobic decomposition of cellulose 



20 Hoppe-Seyler, F. tlber Garung der Cellulose mit Bildung von Methan 

 und Kohlensiiure. Ztschr. physiol. Chem., 10: 201-217; 401-440. 1886. 



21 Omeliansky, 1902 (p. 191). 



22 Iterson, G. van. Die Zersetzung von Cellulose durch aerobe Mikroor- 

 ganismen. Centrbl. Bakt. II, 11: 689-398. 1904. 



