319. The formation of carbon dioxide by lactic acid bacteria andBacillus licheniformisand a cultural method of detecting the process

Abstract

The amount of CO2formed during the fermentation of sugars by the heterofermentative lactic acid bacteria depends on several factors:(1) The sugar fermented. Gas is produced more readily from glucose than from lactose, even in the case of active lactose fermenters.(2) The reaction and the buffering capacity of the medium. The optimum initial reaction of the medium is approximatelypH 7 and the greater the buffering capacity the more active is the gas production.(3) Factors which occur in plant juices and yeast. They may promote gas formation without increasing cell proliferation and apparently have a specific activating effect on the mechanism of the fermentation.(4) The concentration of sugar, the optimum being about 5%.The formation of CO2by Bacillus licheniformis is influenced in a similar way, but in this case the optimum initial reaction of the medium is in the region ofpH 8–9 and the factors of (3) have little effect.