143 



A. HARDEN and J. YOUNG. Alcoholic Ferment of Yeast-Juice. 

 Function of Phosphates in Alcoholic fermentation. 



(Proc. Roy. Soc., 1910, B. 82, pp. 321-330). Jour. Chem. Soc., 

 July 1910. Abs. ii, 643. 



Addition of dextrose or laevulose to yeast-juice in presence of 

 excess of phosphate results in a period of accelerated fermenta- 

 tion; i mol. of carbon dioxide is evolved for each mol. of sugar 

 added. 



When the available phosphate present is greatly reduced, the 

 total fermentation is very small. Addition of small amounts of 

 phosphate produces a relatively large increase in the total fer- 

 mentation. 



A hexosephosphate when digested with yeast-juice is hydrolised 

 by an enzyme, hexosephosphatase, with production of free phosphate 

 and a sugar capable of being fermented by yeast. 



In the chemical changes which the mol. of sugar may undergo 

 in fermentation, 2 mols. of sugar are involved. 



OLIVE EVELINE ASHDOWN and J. TH. HEWITT (East London Col- 

 lege). The By-Products of Alcoholic Fermentation. Journ. 

 of Chem. Soc., London, August 1910, Trans. Pp. 1636-1648. 



The formation of small quantities of carbon compounds other 

 than carbon dioxide and alcohol during the fermentations of various 

 sugars by yeast has attracted much attention and during the past 

 few years considerable light has been thrown on the formation of 

 some of these by-products. 



Comparatively little attention has been devoted to the acetal- 

 dehyde which accompanies the alcohol in varying quantity and 

 which sometimes is formed in considerable amount. 



The occurrence of notable amounts of aldehyde might be re- 

 ferred to one of several possible causes: 



1) Subsequent oxidation of alcohol by atmosferic oxygen. 

 This hypothesis necessitates the presence of a catalytic agent, which 

 might either be derived from an inanimate source, for example some 

 metallic salt the presence of which had been overlooked, or might 

 be of an enzymatic nature and be derived from the yeast or some 

 other organism. 



2) The acetaldehyde may be produced from the sugar by a 

 fermentation due to some other organism. 



