212 THE CARBOHYDRATES 



leaving a neutral product which resembles a typical aldehydic 

 oxycellulose. This is regarded as being due to the oxidation 

 of an alcoholic group into cellulose molecule (see formulae, 

 p. 214). 



4. Action of Ferments. — It has been shown by Brown and 

 Morris, in the case of barley, rye, oat, and other cereals, that 

 the cell wall of the endosperm cells which contain nutrient 

 material are broken down by a cellulose-dissolving ferment, 

 a cyto-hydrolyst, before the embryo can procure the food- 

 stuff contained in these cells. This enzyme, which is de- 

 veloped during the germination of the seed, can be extracted 

 from the malt by cold water, and precipitated from this solu- 

 tion by alcohol. 



A cytase capable of hydrolysing hemicellulose has been 

 extracted from Aspergillus OryzcB, from the cotyledons of 

 Lupinus albus, and Phoenix dactylifera* Cytase splits hemi- 

 cellulose into glucose, mannose, galactose, and pentose, 



Cellulase is an enzyme which attacks ordinary cellulose 

 converting it into cellobiose. It occurs in Aspergillus celluloses^ 

 and in certain bacteria.J It is well known that many fungi, 

 Actinomyces, Aspergillus, Coprinus, Penicillium, and Tricho- 

 derma, § for example, have the power of breaking down 

 cellulose. In this activity they may be of even greater signi- 

 ficance in the soil than the cellulose-splitting bacteria || which 

 belong to the aerobic and the anaerobic forms : of the 

 former Spirochceta cytophaga ^ and Microspora agarlique- 

 faciens ** may be mentioned ; and of the latter those re- 

 sponsible for the subaquatic decomposition of cellulose with 

 the evolution of marsh gas or, in other forms, of hydrogen. 



OXYCELLULOSE. 



When cellulose is exposed to the action of oxidizing agents 

 there results a product which contains a greater proportion of 

 oxygen than the original and is therefore known as oxycellu- 



* Newcombe : " Ann. Bot.," 1899, 13, 49. 



t EUenberger : " Zeit. physiol. Chem.," 1915, 96, 236. 



% Pringsheim : id., 191 2, 78, 266. 



§ Waksman : " Soil Sci.," 1916, 2, 103. 



II See Russell : " The Micro-organisms of the Soil," London, 1923. 



11 Hutchinson and Clayton : " J. Agric. Sci.," 1919, I9> i43- 



** Gray and Chalmers : " Ann. Appl. Biol./' 1924, 11, 324. 



