Study of the content of inorganic polyphosphates in Saccharomyces cerevisiae grown on different carbon sources with different O2 concentrations in the medium

Abstract

The content of different fractions of inorganic polyphosphates (polyP) was studied in Saccharomyces cerevisiae VKM Y-1173 growing on a complete medium with glucose under hypoxia and active aeration as well as on ethanol. The highest growth rate was observed for aerobic fermentation, while the yield of biomass was maximal for cultivation on ethanol. In the mid-log growth phase, the amount of polyP was maximal in the cells grown on glucose under hypoxia and minimal on ethanol. In this latter case, the content of different polyP fractions changed unevenly: polyP3, polyP4, and polyP1 decreased by approximately 60%, 45%, and 30%, respectively; the salt-soluble polyP2 remained at almost the same level; while polyP5 abruptly increased 10- to 15-fold. These findings demonstrate that the metabolic pathways for polyP fractions are different. A significant drop in the amount of the main polyP fractions accompanied by a decrease of the polyP average chain length in the presence of carbon and Pi sources in the medium is evidence of active involvement of polyP as additional energy sources in the flows of energy in actively growing yeast cells.