Biochemistry

In 1937 Snell et al. showed that acetate in the medium for growing lactic acid bacteria might show a function other than buffering. It was shown that the presence of acetate in a medium of peptone, glucose and mineral salts, supplemented with an ether extract of an aqueous potato extract, gave greater acid production by Lactobacillus delbruckii than when supplemented by the potato extract alone. Guirard et al. concluded that acetate may serve a dual purpose: (a) that of a buffer, to prevent the lactic acid formed during growth from lowering the pH of the medium to toxic levels, and (b) an unknown function, concerned with the production of early and luxuriant growth. It was reported that lactic acid bacteria responded to various pure substances supposedly involved in acetate metabolism. The occurrence of a substance or substances in natural materials which duplicated the growth-stimulating effects of acetate for the lactic acid bacteria was also reported. Concentration of the activity was undertaken and a 44-fold concentration was effected, which resulted in a material having 440 times the activity of sodium acetate on a weight basis. The research reported here was undertaken to concentrate the above described active material from natural sources for the purpose of isolating pure material for identification