On the remarkable inhibition of baker's yeast respiration with co-existence of sorbic acid and thiamine or its derivative.

Abstract

The effect of thiamine or Sorbic acid on of bake's yeast was studied and the following findings were obtained.1. A large amount of thiamine stimulated the respiration. Butyryl thiamine disulfide or thiamine diphosphate had rather stronger effect than thiamine hydrochloride. The maximum stimulating effect appeared at the final concentration of 5.5 mM.2. Combined use of thiamine and sorbic acid exhibited the remarkable inhibition of the respiration, i.e., thiamine stimulates the sorbic acid inhibition, and the inhibition increased proportionally to the concentration of the vitamin. Butyryl thiamine disulfide and thiamine diphosphate showed the same interaction, but benzoate, salicylate, dehydroacetate or propionate in place of sorbic acid had no such effect. The remarkable inhibition also appeared with glucose, acetate or pyruvate.3. Sorbic acid incorporation in the cells was not influenced by thiamine. With the cells containing the high level of coenzyme A the stimulating effect of inhibition by thiamine was hardly seen. The results were various according to the lots of yeast. It was confirmed that the different levels of coenzyme A in the cells were the main reason of this variety. It became thus clear that the fact which sorbic acid inhibition was reinforced with the addition of thiamine was related to the coenzyme A level in the cells.4. The yeast growth was also markedly inhibited by the combined addition of thiamine and sorbic acid in the shaking culture, but in the stationary culture the characteristic inhibition was not recognized.