DECOMPOSITION OF NON-NITROGENOUS ORGANIC MATTER 435 



bacteria decompose celluloses with the formation of a clear zone around 

 the colony, indicating the formation of an exo-cellular enzyme; 27 other 

 microorganisms, especially certain fungi and bacteria, can utilize cellu- 

 lose without the production of a clear zone on the cellulose plate, in- 

 dicating the endo-nature of the corresponding enzyme. 



Pringsheim 28 allowed the decomposition of cellulose to proceed till 

 a maximum has been reached, as indicated by gas formation. Bac- 

 terial action was then quickly brought to a standstill by the introduc- 

 tion of a proper antiseptic, which prevented the further development 

 of the bacteria without injuring the enzyme cellulase. The products 

 of hydrolysis (sugars) will then accumulate, due to the fact that the 

 sudden stop of bacterial action does not prevent the hydrolytic en- 

 zyme (cellulase) from breaking down the cellulose. The hydrolytic 

 products cellobiose and glucose are demonstrated by the reduction of 

 Fehling 's solution, and formation of corresponding osazones. 



Since the decomposition of cellulose is a comparatively slow proc- 

 ess, especially at normal temperatures, the hydrolytic action of the 

 enzyme is also very slow and does not lead to any abundant accumu- 

 lation of products of hydrolysis. This, as well as the destruction of 

 the hydrolytic enzymes by proteolysis, suggested the use of large 

 quantities of media which are concentrated in vacuo, at a low tempera- 

 ture, so as to obtain a solution with a sugar concentration sufficient 

 for identification. In the methane, hydrogen, and denitrifying proc- 

 esses, it takes two to seven days before reducing sugar can be demon- 

 strated. The thermophilic bacteria, which are much more active, 

 give a strong reduction of Fehling solution in 24 hours. 



Just as starch is hydrolyzed by amylase at first to the disaccharide 

 maltose and then by a separate enzyme (maltase) to glucose, so is 

 cellulose first hydrolyzed by the cellulase of bacteria to the disaccharide 

 cellobiose, then by the enzyme cellobiase to glucose. The latter en- 

 zyme has also been demonstrated in cellulose decomposing bacteria 

 and fungi. 29 



"Kellerman and McBeth, 1912 (p. 197). Lohnis, F., and Lochhead, G. 

 Experiments on the decomposition of cellulose by aerobic bacteria. Centrbl. 

 Bakt. II, 58: 430-434. 1923. 



28 Pringsheim, H. tlber den fermentativen Abbau der Zellulose. Ztschr. 

 physiol. Chem., 78: 266-291. 1912. 



29 Fischer, E., and Zemplen, G. Verhalten der Cellobiose und ihres Osons 

 gegen einige Enzyme. Liebig's Ann. Chem., 335: 1-6. 1909: 372: 254-256. 

 1910; Bertrand, G., and Holderer, M. La cellase et le d^doublement diastatique 

 du cellose. Compt. Rend. Acad. Sci., 149: 1385. 1909; 150: 230. 1910. 



