Metabolomic Profiling of Endomyces magnusii During Long-Term Cultivation on Glycerol and Glucose

The study purpose was to identify possible key metabolites that determine the adaptation of the Endomyces magnusii yeast to long-term cultivation (four weeks) using glycerol as an "oxidative" and glucose as a "fermentative" substrate.

The metabolic profile was assayed using gas chromatography combined with mass spectrometry, followed by bioinformatic analysis (PARADISe, Golm metabolome database (GMD), MassBank, UniChrom).

PCA and PLS-DA analyses showed that the type of carbon source contributed significantly to the overall variability of the data, and the greatest variance was observed for the groups grown on different substrates for the first cultivation week. Growth on glycerol increased the chronological lifespan of E. magnusii due to the early launch of adaptive oxidative stress, the active use of lipids as an energy source, the accumulation of membrane sterols, osmo-protective polyols, organic acids (malic, methyl glycerinic, palmitic, linoleic), and some sugars (lyxose, galactose), which increased the overall resistance and maintained high cell survival. On the contrary, cultivation using glucose provoked a sharp substrate depletion, inducing passive storage of sugars (trehalose), diauxic shock, and less effective antioxidant protection, which provided lower cell survival upon prolonged growth.

(1) Metabolic signs associated with prolonged culturing were identified in all the compounds classes tested (polyols, fatty acids, lactones); (2) some metabolites (in particular, dulcitol), being hypothetical biomarkers of aging, are at the same time protective agents involved in the adaptation of yeast cells to the deep stationary growth stages. Our data can serve as a basis for comparative studies of aging-related metabolism in other eukaryotic models.