Nitrogen Metabolism in Saccharomyces cerevisiae

DURING the last few years, the assimilation of nitrogen by the lower organisms of the vegetable kingdom has formed the subject of an ever-increasing number of investigations, the results of which have rendered evident the great im- portance of this question in its bearing on the problems of both pure and applied chemistry.Of these researches, not the least suggestive, from a purely chemical, as well as from an industrial, standpoint are those of Felix Ehrlich and his collaborators, who succeeded in establishing the fact that the "fusel oil" of the distiller is produced by the action of yeast on the amino-acids in the wort, yielding the corresponding alcohols, such amino-acids being the degradation products of the proteins originally present.It is not necessary to trace the history of this theory, first put forward bv A. Muller in 1857, and either disregarded or discredited until Ehrlich in 1903 proved that the a-amino-acids when treated with yeast in a saccharine solution give the corresponding alcohols.The object of the work described in the present communication was the closer investigation of those factors which affect the nitrogen metabolism in yeast, not only from the point of view of the assimilation of the nitrogen detached from the amino-acid during its conversion into an alcohol, but also from the point of view of an apparent excretion of nitrogen which takes place with yeast under certain circumstances.