Some Factors Involved in the Biological Production of Acetone and Butyl Alcohol

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Abstract
A study of 6 strains of Clostridium acetobutylicum showed their morphological and cultural characteristics to be essentially as described by Weyer and Rett-ger (1926). Studies of the acid- and solvent producing power of these organisms showed that in semi-synthetic media their acid production curves were not identical with those described by Robinson (1922). All of the strains studied produced high acidity which, however, did not decrease during the entire course of the fermentation in the semi-synthetic medium employed. This maintenance of high acidity was always correlated with an almost complete absence of butyl alcohol as one of the end products of fermentation, and production of normal quantities of acetone. A study of the effect of various substances and conditions on formation of butyl alcohol in semi-synthetic media showed that, within definite limits, pH, % of peptone, various salts, method of anaerobiosis, various water-soluble proteins, and certain fats played no definite role in formation of butanol. However, the alcohol-soluble protein from corn, oats and barley, when added in a concentration of 4-5%, led to production of normal amounts of butyl alcohol in the semi-synthetic medium used. It was concluded from data available that an alcohol-soluble protein, or some substance closely allied to it, must be present in a medium in order to promote formation of butyl alcohol from a fermentable carbohydrate by Cl. acetobutylicum. Exps. were carried out to show that the alcohol-soluble substance did not act as a catalyst in the reaction; nor was the butanol found to be derived from the substance itself. The action of the alcohol-soluble substance was apparently physico-chemical.