Alcoholic fermentation / by Arthur Harden.

  • Arthur Harden
Date:
1932
Catalogue details

Licence: In copyright

Credit: Alcoholic fermentation / by Arthur Harden. Source: Wellcome Collection.

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    inactivated by dialysis, or to dried yeast which had been washed with water and then treated with acetone. At a later period Harden [1917] found that washed zymin, prepared by treating top yeast with acetone, could be activated by pyruvates and by acetaldehyde, in presence of phosphate, provided that potassium ions were present, whereas no activation occurred in their absence. Thus when sodium phosphate was used, potassium pyruvate produced activation whereas the sodium salt did not, and acetaldehyde similarly produced no effect in presence of sodium phosphate, whereas in presence of potassium phosphate vigorous fermentation was produced. Neuberg, however [1918, 1], was unable to obtain this result with preparations from bottom yeast and considered that a mixture of ketonic acids was essential. Meyerhof [1918, 1] found that when thoroughly washed the filtration residue from maceration extract (bottom yeast) was not activated by sodium pyruvate, and several workers [Kluyver and Struyk, 1927 ; Stheeman, 1929 ; Myrback, 1928] have found that zymin and dried yeast when sufficiently washed cannot be activated by pyruvates or aldehydes whereas they are activated by boiled yeast washings. This has also been confirmed in the author’s laboratory [Harden and Macfarlane, 1931]. Meyerhof further observed that in washing ultrafiltration residue a stage is reached at which the residue will no longer ferment sugar but still ferments hexosediphosphate. He at first was inclined to think that the fermentation of hexosediphosphate could be effected without the aid of the co-enzyme but ultimately found that this was not the case, and that the thoroughly washed residue could not ferment hexosediphosphate, a fact confirmed by many workers. On the fact that hexosediphosphate requires a smaller concentration of co-enzyme for its fermentation than does sugar, he has based a theory of the direct fermentation of hexosediphosphate, without re-esterification of the hexose (p. 141). The whole question has been re-investigated first by Kluyver and Struyk [1927, 1928, 2], and then by Stheeman [1929, 1930], who have found that several stages of inactivation of maceration residue and zymin by washing with water can be distinguished. An important point to bear in mind is that different preparations vary considerably in the ease with which they can be deprived of co-enzyme and other soluble constituents by washing. Zymin or dried yeast from bottom yeast is usually much more easily freed from co-enzyme by washing than are the corresponding preparations from top yeast [see Neuberg and Gottschalk, 1925, 3], but the rule is not invariable.
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