Transfer of Sulfite in Medium to the Cells of Wine Yeast

Abstract

1. In the pH 7.0 medium with 520.3mg/l (5mM) sodium hydrogen sulfite added, the yeast grew rapidly in the initial stage, gradually reduced its growth rate, and then recovered its initial growth rate.
2. Free SO₂ at the beginning of culture decreased with the growth of the yeast, and mostly changed to combined SO₂ after about 20 hr.
3. In the radioisotope NaH³⁵SO₃ experiment, loss of sulfite added to the medium as ³⁵S0₂ gas was not found.
4. From the result of the radioisotope and bioassay experiments, we suppose that total sulfite decreased because of the change of a part of sulfite to non-volatile sulfur compounds.
5. About 99% of ³⁵S in the cells was transferred as S0₃^2- from the medium and residual 1% was transferred as non-volatile sulfur compounds which was produced from SO₂^3- by oxidation in the medium.