Fermentative activity of promising yeasts for cereal-based beverages using CO₂ headspace analysis

This article proposes an approach based on the evaluation of CO2 produced by Saccharomyces cerevisiae var. boulardii, Kluyveromyces lactis × Saccharomyces cerevisiae, Saccharomyces pastorianus var. pastorianus, Kazachstania exigua, as a function of different media (laboratory media with glucose and maltose) and sugars to screen promising yeasts for cereal-based beverages. Data were modelled by the Gompertz equation to estimate the time of metabolic adaptation (λ), the rate of CO2 production (kmax), and the maximum concentration of CO2 [(CO2)max]. Kl. lactis showed the lowest value of (CO2)max, which suggests an "attenuated" metabolic response in the medium containing glucose. K. exigua showed a reduced production of CO2 in the presence of maltose; however, the decrease of (CO2)max was not related to an increase of λ.