Biosynthesis of Proteinases and Pectinases by Wine Yeasts

Abstract

The relevance of research is determined by the need to use the biological potential of wine yeast to improve the quality of wines and ensure their stability against colloidal turbidity. The purpose of the research is to determine the activity of enzyme systems, proteinases,and pectinases, synthesized by wine yeast during alcohol fermentation and autolysis, depending on their race and the duration of contact of the wine material with yeast biomass. To determine the enzyme activity, yeasts of different strains were incubated on media containing the following substrates: albumin for proteinases, apple pectin for pectinases. The biosynthesis of proteinases and pectinases by various races of wine yeast was studied as well as their secretion into wine material. The research has shown that the activity of proteinases in the cell biomass and wine materials varies widely depending on the race of the yeast, which is explained by their genetic characteristics. The absence of a correlation between the activity of proteinases in yeast biomass and wine material has been established. For the first time, it has been shown that the biomass of active dry yeast cells has a large supply of proteinases in comparison with the yeast starters of races produced in Russia. The activity of pectinases in yeast biomass is significantly less than the activity of proteinases, which is due to a lower concentration of the substrate - pectin substances. The paper suggests several interpretations of the mechanisms of biochemical processes occurring during the contact of yeast biomass and wine materials. The paper contains experimental data on the effect of proteinases and pectinases synthesized by wine yeast on the composition of wine biopolymers. The study identifies the yeast strains that actively hydrolyze the high-molecular components of wine and complexes of biopolymers, and prolong the resistance of wines to colloidal turbidity.