Growth kinetics and Pho84 phosphate transporter activity of Saccharomyces cerevisiae under phosphate-limited conditions

Abstract

The effect of phosphate (Pi ) concentration on the growth behavior of Saccharomyces cerevisiae strain CEN.PK113-5D in phosphate-limited batch and chemostat cultures was studied. The range of dilution rates used in the present study was 0.08-0.45 h-1. The batch growth of yeast cells followed Monod relationship, but growth of the cells in phosphate-limited chemostat showed change in growth kinetics with increasing dilution rates. The difference in growth kinetics of the yeast cells in phosphate-limited chemostat for dilution rates below and above approximately 0.2 h-1 has been discussed in terms of the batch growth kinetic data and the change in the metabolic activity of the yeast cells. Immunological detection of a C-terminally myc epitope-tagged Pho84 fusion protein indicated derepressive expression of the Pho84 high-affinity Pi transporter in the entire range of dilution rates employed in this study. Phosphate transport activity mediated by Pho84 transporter was highest at very low dilution rates, i.e. 0.08-0.1 h -1, corresponding to conditions in which the amount of synthesized Pho84 was at its maximum. © 2006 Society for Industrial Microbiology.