Prefectural Government, Nagoya. 451 Changes in several components of synthetic and natural medium were measured during acetic acid fermentation. (1) Effective substances such as glycerol, lactic acid, L-alanine, L-aspartic acid and D-glucose, were supplemented to the basal medium respectively. Decrease of glycerol was more than any other substances and was remarkable in the early stage of the fermentation. L-alanine enhibited slight decrease, and L-aspartic acid was converted to L-alanine in

more »

... early stage of acetic acid fermentation. (2) In the three kinds of natural medium, including sake cake, yeast extract and non-salt soybean miso, glycerol content showed a remarkable decrease in all of the media tested . Among the non-volatile organic acids, significant decrease of lactic acid content was observed in the yeast extract medium, whereas the amounts of succinic and citric acid were hardly changed . As the acetic acid fermentation progressed, total amino acid contents decreased gradually in all of the media tested. In particulary, glutamic acid, aspartic acid and serine contents decreased considerably at the early stage of acetic acid fermentation.