Recent Research: Quantifying Wine Yeast Using Phenomics
January 09, 2019
I’ve been hearing a lot of words ending in “-omics” in recent years. Of course some “-omics” words like economics are quite venerable, but now I’m hearing things like genomics, metabolomics, lipidomics, transcriptomics, and phenomics when discussing grape and wine research. They all refer to measuring change with the prefix referring to what is measured or what is changing. Thus phenomics, is the measurement of phenomes, the physical and biochemical traits of an organism, as they change. The changes themselves may be caused by the physical environment or genetic mutation. For fermentation studies, phenomics offers a way to study the enological factors that affect the performance of individual yeast strains. The paper was publish by PLOS ONE with open access (no paywall) and may be found online at the links below.
This work describes the set up of a small scale fermentation methodology for measuring quantitative traits of hundreds of samples in an enological context. By using standardized screw cap vessels, the alcoholic fermentation kinetics of Saccharomyces cerevisiae strains were measured by following their weight loss over the time. This dispositive was coupled with robotized enzymatic assays for measuring metabolites of enological interest in natural grape juices. Despite the small volume used, kinetic parameters and fermentation end products measured are similar with those observed in larger scale vats. The vessel used also offers the possibility to assay 32 volatiles compounds using a headspace solid-phase micro-extraction coupled to gas chromatography and mass spectrometry. The vessel shaking applied strongly impacted most of the phenotypes investigated due to oxygen transfer occuring in the first hours of the alcoholic fermentation. The impact of grape must and micro-oxygenation was investigated illustrating some relevant genetic x environ- mental interactions. By phenotyping a wide panel of commercial wine starters in five grape juices, broad phenotypic correlations between kinetics and metabolic end products were evidentiated. Moreover, a multivariate analysis illustrates that some grape musts are more able than others to discriminate commercial strains since some are less robust to environmental changes.