Genetic improvement of Saccharomyces cerevisiae wine strains for enhancing cell viability after desiccation stress

Abstract

In the last few decades spontaneous grape must fermentations have been replaced by inoculated fermentation with Saccharomyces cerevisiae strains as active dry yeast (ADY). Among the essential genes previously characterized to overcome the cell-drying/ rehydration process, six belong to the group of very hydrophilic proteins known as hydrophilins. Among them, only SIP18 has shown early transcriptional response during dehydration stress. In fact, the overexpression in S. cerevisiae of gene SIP18 increases cell viability after the dehydration process. The purpose of this study was to characterize dehydration stress tolerance of three wild and one commercial S. cerevisiae strains of wine origin. The four strains were submitted to transformation by insertion of the gene SIP18. Selected transformants were submitted to the cell-drying-rehydration process and yeast viability was evaluated by both viable cell count and flow cytometry. The antioxidant capacity of SIP18p was illustrated by ROS accumulation reduction after H 2 O 2 attack. Growth data as cellular duplication times and lag times were calculated to estimate cell vitality after the cell rehydration process. The overexpressing SIP18 strains showed significantly longer time of lag phase despite less time needed to stop the leakage of intracellular compounds during the rehydration process. Subsequently, the transformants were tested in inoculated grape must fermentation at laboratory scale in comparison to untransformed strains. Chemical analyses of the resultant wines indicated that no significant change for the content of secondary compounds was detected. The obtained data showed that the transformation enhances the viability of ADY without affecting fermentation efficiency and metabolic behaviour.

Biotechnological impact of stress response on wine yeast

“…High levels of protective disaccharide trehalose, and strong catalase and glutathione reductase activities, have been related with good drying performance in wine (Gamero-Sandemetrio et al 2014). The overexpression of hydrophilin SIP18 in industrial strains decreases ROS after oxidative stress and increases viability after desiccation (Lopez-Martinez et al 2013). Once again, this proves that increased stress tolerance can improve ADY production.…”

“…The overexpression of hydrophilin SIP18 in industrial strains decreases ROS after oxidative stress and increases viability after desiccation (Lopez‐Martinez et al . ). Once again, this proves that increased stress tolerance can improve ADY production.…”

Selected Indigenous Saccharomyces cerevisiae Strains as Profitable Strategy to Preserve Typical Traits of Primitivo Wine

“…The content of the major volatile compounds of the final wines were analyzed by a GC glass column packed, as previously reported. Other aromatic compounds, such as acetates and ethyl esters, volatile fatty acids, and terpenes were analyzed by SPME-GC-MS in splitless mode with a DB-WAXTER (Agilent) column, following the procedure described by López-Martínez et al [28].…”

Production, reactivation and nutrient requirements of active dried yeast in winemaking: theory and practice

“…Yeast strain resistance to oxidation is a critical factor in the ability of yeast to survive dehydration (López‐Martínez et al. ). Both propagation and drying processes exposes yeast to oxidative damage, with lipid peroxidation and protein carbonylation the result (Garre et al.…”