A New Phosphoric Ester Isolated from the Products of Yeast Juice Fermentation

Abstract

THE fermentation hexosemonophosphate (Robison ester¹) isolated from the products of fermentation of glucose, mannose, or fructose by yeast juice, consists mainly of an enzymic equilibrium mixture of glucose-, fructose- and mannose-6-phosphates^2,3, but as usually purified by means of the lead and barium salts may also contain traces of trehalosemonophosphate, phosphopyruvic acid, triosephosphate, a-glycerophosphate, etc. A typical specimen of the Robison ester also gives a green colour when heated with orcinol and hydrochloric acid, the amyl alcohol extract showing an absorption band about 670 m&µ. This fact indicates the presence of an unknown ester in the mixture, since the reaction is not given by any of the above-mentioned phosphoric esters, and differs from that given by pentoses (in absence of iron) in the position of the absorption band ; it was found, however, that an identical reaction is given by the 7-carbon atom sugar mannoketoheptose, isolated from the Avocado pear by La Forge⁴.