The intracellular level of free inorganic orthophosphate (Pi) in yeast cells generally depends on the Pi uptake capacity, energy state of the cells in respect to the activity of the membrane-associated ATPases and on the activity of metabolic pathways involved in the production of glycerol and trehalose. Batch fermentation was performed to investigate the carbon substrate consumption, the Pi uptake capacity and product formation by four Saccharomyces cerevisiae strains differing in their ability to produce glycerol and/or trehalose. The consumption of Pi in mutant strains with a lack of the synthesis of the trehalose and/or glycerol exceeded the level for a wild type strain about two times. Maximum intracellular polylP content (29.9 mg/g DW) was shown for tps1 Delta gpd1 Delta mutant. In this study we showed that the P-i uptake and polyP accumulation level were closely connected with the changes in the synthesis of trehalose and glycerol. (c) 2006 Elsevier Ltd. All rights reserved.