Abstract
In the previous paper an increase of lactic acid formation was shown when lactic acid bacteria were grown on a milk culture medium containing the aqueous extract of KUKO leaves.
In this paper the stimulation of bacterial growth were attributed to amphoteric sub-stances by the following observations. Active principles could not be extracted by organic solvents such as n-butanol or ethyl acetate at pH values of 9 and 2, and were adsorbed on the columns of Amberlite IR-120 and IR-410. The eluates from the column of Amberlite IR-120 were further fractionated to three fractions-acidic, basic and neutral-using Amberlite IR-4 B and IRC 50. The neutral fraction (containing neutral amino acids) and the basic fraction (containing bases and basic amino acids) showed stimulating effect on acid formation of Lact. acidophilus, Lact. bulgaricus, Lact. casei and Sc. faecalis.
