Detoxification capacities of heavy metals and pesticides by yeasts
Winegrowing is still characterized by the extensive use of chemical fertilizers and plant protection products, despite strong recommendations to limit these practices. A part of these xenobiotics and metals are then found in grape juice and wine, causing a major health concern, as well as negatively affecting the fermentation process. In recent years, there has been renewed interest in non-Saccharomyces yeasts. These species have a wide phenotypic diversity, which would be exploited to broaden the aromatic palette of wines. The potential of some of these species as a bio-protection agent, in pre-fermentation treatment, has also been established.
In addition to these characteristics, the heavy metal sorption capacities of these species are mentioned in the literature. Pre-fermentation treatment of the harvest with non-Saccharomyces (NS) yeasts therefore appears to be an alternative to the use of chemical inputs for the elimination of organic and inorganic xenobiotics from grape musts. However, our knowledge of the detoxification capacities of yeasts and their molecular and biochemical determinant is not yet sufficiently advanced to allow such methods to be developed and put into practice. In this study, we investigated the detoxifying abilities of fourteen strains of Saccharomyces and non-Saccharomyces yeasts during the first stages of wine fermentation. Fermentations were conducted in synthetic must in the presence or absence of pesticides (mix of twenty pesticides commonly used in the vineyard) / metals (copper). The colorimetric determination of copper concentration throughout fermentation revealed that most Saccharomyces and non-Saccharomyces yeasts detoxify almost all copper in less than 48 hours. Regarding pesticides detoxification, quantified by GC-MS (Dubernet laboratory), a higher variability was observed, with a removal of 0% to 90% of the compound depending on the yeast strain and the pesticide. In conclusion, this study showed the great diversity of the capacity of yeasts to detoxify molecules used in vineyards to fight against diseases and/or parasites and the biotechnological potential that this represents.
Issue: ICGWS 2023
1SPO, INRAe, Institut Agro Montpellier, Montpellier, France
2LALLEMAND SAS, Blagnac, France
3Laboratoire Dubernet, Narbonne, France