The role of myoinositol in metabolic control. II. The effects of medium constituents and other factors on acetoin accumulation in Saccharomyces carlsbergensis 4228 (ATCC 9080).

Abstract

The accumulation of acetoin in the culture medium of Saccharomyces carlsbergensis was specific with m-I deficiency. Its concentration in 48 hour culture medium reached to 8 μmoles/mg of dry cell and the ratio of acetoin production by the m-I deficient yeast to that by the normal yeast (m-I supplemented) was found to be 100-1000 in 48 hour cultivation in one of four media tested. Casein hydrolysate used as nitrogen source in the medium, changed this ratio greatly by their lots. pH during the cultivation changed slightly (between 4.5 and 5.0) and it gave no significant effects on acetoin accumulation. Addition of increased amount of ammonium sulfate to the medium gave an adverse effect on the growth of m-I deficient yeast and accelerated the acetoin accumulation. While the addition of cofactors for pyruvate oxidation such as lipoic acid, had no reducing effect for acetoin production, the addition of thiamine was critical for it in m-I deficient Saccharomyces carlsbergensis.