OENO IVAS 2019 banner
IVES 9 IVES Conference Series 9 OENO IVAS 9 OENO IVAS 2019 9 Grape and wine microorganisms: diversity and adaptation 9 Mathematical modeling of fermentation kinetics: a tool to better understand interactions between Torulaspora delbrueckii and Saccharomyces cerevisiae in mixed cultures

Mathematical modeling of fermentation kinetics: a tool to better understand interactions between Torulaspora delbrueckii and Saccharomyces cerevisiae in mixed cultures

Abstract

Nowadays the use of Torulaspora delbrueckii is more and more common in winemaking. However, its behavior in presence of Saccharomyces cerevisiae is not always predictable. Indeed, the interactions existing between the two yeasts are still not well characterized and can lead to a bad control during their implementation in mixed cultures. The objective of the work presented here was to use the mathematical modeling as a tool to better understand microbial interactions in this context. 

Mixed cultures of a couple of oenological yeasts composed of T. delbrueckii and S. cerevisiae were carried out on a synthetic grape must in anaerobiosis. The impact of various parameters was evaluated: assimilable nitrogen concentration, direct and indirect contact (thanks to a membrane bioreactor), increase of lipids concentration (Tween 80 and ergosterol). 

The analysis of experimental data acquired during the pure cultures of each yeast enable to establish a mathematical model to describe the fermentation kinetics for pure cultures. Then this model was used to predict the kinetics of mixed cultures without any interaction except competition for substrates (sugar and nitrogen). The comparison between predicted and experimental kinetics showed that in mixed culture several kind of interactions must be taken into account: competition for space, cell to cell contact, reciprocal stimulation. Moreover, at low lipids initial concentration, S. cerevisiae dominated T. delbrueckii by producing a toxic metabolite. An increase in the initial lipids concentration completely reversed this domination.

DOI:

Publication date: June 10, 2020

Issue: OENO IVAS 2019

Type: Article

Authors

Patricia Taillandier, Cedric Brandam, Sandra Beaufort, Paul Brou

LGC université de Toulouse – 4 alle Emile Monso CS 84234 – 31432 Toulouse Cedex4

Contact the author

Keywords

modeling, interaction, Saccharomyces, Torulaspora 

Tags

IVES Conference Series | OENO IVAS 2019

Citation

Related articles…

Lactic acid bacteria: A possible aid to the remediation of smoke taint?

With climate change, the occurrence of wildfires has increased in several viticultural regions of the world. Subsequently, smoke taint has become a major issue, threatening the sustainability of the wine industry.

What are the optimal ranges and thresholds for berry solar radiation for flavonoid biosynthesis?

In wine grape production, canopy management practices are applied to control the source-sink balance and improve the cluster microclimate to enhance berry composition. The aim of this study was to identify the optimal ranges of berry solar radiation exposure (exposure) for upregulation of flavonoid biosynthesis and thresholds for their degradation, to evaluate how canopy management practices such as leaf removal, shoot thinning, and a combination of both affect the grapevine (Vitis vinifera L. cv. Cabernet Sauvignon) yield components, berry composition, and flavonoid profile under context of climate change. First experiment assessed changes in the grape flavonoid content driven by four degrees of exposure. In the second experiment, individual grape berries subjected to different exposures were collected from two cultivars (Cabernet Sauvignon and Petit Verdot). The third experiment consisted of an experiment with three canopy management treatments (i) LR (removal of 5 to 6 basal leaves), (ii) ST (thinned to 24 shoots per vine), and (iii) LRST (a combination of LR and ST) and an untreated control (UNT). Berry composition, flavonoid content and profiles, and 3-isobutyl 2-methoxypyrazine were monitored during berry ripening. Although increasing canopy porosity through canopy management practices can be helpful for other purposes, this may not be the case of flavonoid compounds when a certain proportion of kaempferol was achieved. Our results revealed different sensitivities to degradation within the flavonoid groups, flavonols being the only monitored group that was upregulated by solar radiation. Within different canopy management practices, the main effects were due to the ST. Under environmental conditions given in this trial, ST and LRST hastened fruit maturity; however, a clear improvement of the flavonoid compounds (i.e., greater anthocyanin) was not observed at harvest. Methoxypyrazine berry content decreased with canopy management practices studied. Although some berry traits were improved (i.e. 2.5° Brix increase in berry total soluble solids) due to canopy management practices (ST), this resulted in a four-fold increase in labor operations cost, two-fold decrease in yield with a 10-fold increase in anthocyanin production cost per hectare that should be assessed together as the climate continues to get hot.

Climate change projections to support the transition to climate-smart viticulture

The Earth’s system is undergoing major changes through a wide range of spatial and temporal scales as a response to growing anthropogenic radiative forcing, which is pushing the whole system far beyond its natural variability. Sources of greenhouse gases largely exceed their sinks, thus leading to a strengthened greenhouse effect. More energy is thereby being supplied to the system, with inevitable shifts in climatic patterns and weather regimes. Over the last decades, these modifications have been manifested in the full statistical distributions of the atmospheric variables, with dramatic changes in the frequency and intensity of extremes. Natural hazards, such as severe droughts, floods, forest fires, or heatwaves, are being triggered by extreme atmospheric events worldwide, thus threatening human activities. Viticultculture is not only exposed to changing climates but is also highly vulnerable, as grapevine phenology and physiological development are strongly controlled by atmospheric conditions. Therefore, the assessment of climate change projections for a given region is critical for climate change adaptation and risk reduction in viticulture. By adopting timely and suitable measures, the future sustainability and resiliency of the sector can be fostered. Climate-grapevine chain modelling is an essential tool for better planning and management. However, the accuracy of the resulting projections is limited by many uncertainties that must be duly taken into account when transferring knowledge to stakeholders and decision-makers. Climate-smart viticulture will comprise ensembles of locally tuned strategies, envisioning both adaptation and mitigation, assisted by emerging technologies and decision-support systems.

Key odorants responsible for the sensory spaces defining the different aroma potentials of Grenache and Tempranillo grapes

There are yet many gaps in our knowledge about the aroma potential of winemaking grapes and its measurement. Trying to bring some light into this question, a new general strategy based on the accelerated hydrolysis of reconstituted phenolic and aromatic fractions (PAFs) extracted from grapes has been developed

Phloem anatomy traits predict maximum sugar accumulation rates

Heat and water stress can accelerate berry sugar accumulation and lead to excessive sugar-to-acid ratios at harvest, producing bland, overly-alcoholic wines. Selecting grapevines for slower sugar accumulation could help maintain wine quality under future, hotter conditions, but these efforts have been stymied by our limited understanding of the traits determining sugar accumulation rates. Here, we measured traits characterizing the structure and anatomy of the sugar transport system – the phloem – in 16 winegrape cultivars and tested for relationships with sugar accumulation rates and cultivar climate classifications.