Production of H 2 S and properties of sulfite reductase from selected strains of wine-producing yeasts

Abstract

Correlation between H2S productivity (p) and sulfite reductase activity (A) was estimated for seven wine-producing yeasts. It was described by a linear function p=f(A), the slope of which depended on the yeast strain. The most intensive H2S synthesis by all the examined yeasts was observed within the early logarithmic growth phase, either in nitrogen abundance and SO2 presence, or in nitrogen deficient and SO2-free medium. Sulfite reductase from all the strains was optimally active at pH close to 7.4. The enzyme from cryophilic yeasts displayed maximum activity at approximately 16 °C, and from mesophiles at 22–26 °C. The preparations showed different affinities toward sulfite (K m of 16.7–67.5 μM). Values of activation energy in sulfite reduction depended on the yeast, and ranged from 14.07 to 67.04 kJ mol−1.