Non-Saccharomyces wine strains face problems during biomass propagation due to low invertase and stress tolerance

Abstract:

In the winemaking industry, the use of active dry yeast (ADY) as inoculum is a well-established practice, due to its long-term stability. During industrial biomass propagation, yeast cells undergo a series of stresses, oxidative stress being the main one, which affect biomass yield and fermentative capacity of ADY. Recently, there has been an increasing interest in using non-Saccharomyces wine yeasts as inoculums in mixed fermentations, and there are already commercially available strains. Saccharomyces cerevisiae is well adapted to the biomass propagation process. However, some non-Saccharomyces species show defective growth in these conditions, mostly due to their lower tolerance to oxidative stress. Two non-Saccharomyces species Hanseniaspora vineae and Metschnikowia pulcherrima, which show distinct behaviour in ADY production tests, were tested. We observed differences in their oxidative stress defence mechanisms that correlate with their performance in ADY production conditions. We have detected that both species are incapable of fully depleting the sucrose present in molasses, linked to their low invertase activity. Acid hydrolysis with HCl allowed full hydrolyzation of sucrose permitted cells to consume all the available sugars. Our results validate that molasses hydrolyzation prior to growth in bench-top and bioreactor trials can have a beneficial effect on biomass yield and fermentative capacity of non-Saccharomyces ADY. In order to find new strains useful for their use as starters, yeasts isolated from traditional Ecuadorian chichas were tested for stress tolerance and growth on molasses. Three S. cerevisiae strains and …

Año de publicación:

2019

Keywords:

Fuente:

google