The specific nutritive requirements of Clostridium acetobutylicum (Weizmann). II

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Abstract
For normal butanol-acetone fermentation (i.e., a fermentation comparable, in yield of products and in fermentation intensity, to the butanol-acetone fermentation of a 2.5% maize mash) in a synthetic medium, the presence of biotin in addition to asparagine is necessary [see B. A. 12(1): entry 1348]. This was determined by quantitative comparison of the stimulating effect of extracts prepd. both from egg yolk and from maize according to the procedure described by Kogl and Toennis (Hoppe-Seylers Zeitschr. Physiol. Chem. 243: 43. 1936) on the fermentation intensity of a butanol-acetone fermentation, and was confirmed by a quantitative comparison of the known relative biotin content of maize compared with parsley and cress seed using C. acetobutylicum as test object. The figures quoted by Kogl and Haagen-Smit (Hoppe-Seylers Zeitschr. 243: 209. 1936) with yeast as test object and expressed as Activator Units (maize, 1.3 A. U. per g.; parsley, 10.6 A. U. per g.; and cress, 112 A. U. per g.) are in satisfactory agreement with the figures obtained with C. acetobutylicum (maize, 13 A. U. per g.; parsley, 9.8 A. U. per g.; and cress, 8.1 A. U. per g.).[long dash]Asparagine plus biotin (in a synthetic sugar medium) reach 70% of the nutritional level of a maize mash as measured by the fermentation intensity; complete attainment of the nutritional level of maize mash required the addition of a dialysate from yeast autolysate, which on storage had lost its biotin activity, to a medium containing biotin plus asparagine. This "third factor" is a stable substance of low mol. wt. and unknown chem. composition.