Quantitative analysis of 3-OH oxylipins in fermentation yeast

Abstract

Despite the ubiquitous distribution of oxylipins in plants, animals, and microbes, and the application of numerous analytical techniques to study these molecules, 3-OH oxylipins have never been quantitatively assayed in yeasts. The formation of heptafluorobutyrate methyl ester derivatives and subsequent analysis with gas chromatography – negative chemical ionization – mass spectrometry allowed for the first determination of yeast 3-OH oxylipins. The concentration of 3-OH 10:0 (0.68–4.82 ng/mg dry cell mass) in the SMA strain of Saccharomyces pastorianus grown in laboratory-scale beverage fermentations was elevated relative to oxylipin concentrations in plant tissues and macroalgae. In fermenting yeasts, the onset of 3-OH oxylipin formation has been related to fermentation progression and flocculation initiation. When the SMA strain was grown in laboratory-scale fermentations, the maximal sugar consumption rate preceded the lowest concentration of 3-OH 10:0 by ∼4.5 h and a distinct increase in 3-OH 10:0 concentration by ∼16.5 h.