An Unknown Factor Stimulating the Formation of Butyl Alcohol by Certain Butyric Acid Bacteria

Abstract

A substance greatly stimulating fermentation of corn-mash by certain butyric acid bacteria was found in potatoes, oranges, lettuce, and in many other plant materials. Furthermore, water extracts of these materials from which glucose, carbohydrates hydrolyzable to glucose and proteins had been removed by treatment with ammoniacal lead acetate, were still effective in stimulating fermentation of corn. The effect of the unknown stimulant is to increase greatly the destruction of starch, and to increase the production of butyl alcohol more than tenfold. Yields of other solvents (acetone and ethyl alcohol) were not affected. On the basis of dry matter, lettuce, cabbage and orange contained 5-10 times as much stimulant as the other plant materials tested. Different strains of the bacteria differed widely in degree of response to this stimulant.