Characterization of potassium, sodium and their interactions effects in yeasts

Abstract

Biotechnology processes rely on the efficiency of microbial cell factories. The budding yeast Saccharomyces cerevisiae is an important cell factory but shows a limited native substrate-product spectrum. Non−conventional yeasts with diverse origins can potentially broaden this spectrum. Here, we benchmarked non−conventional yeasts Kluyveromyces marxianus (KM) and Rhodotorula toruloides (RT) against S. cerevisiae CEN.PK and W303 strains. We developed a computational method for quantification of cellular/organellar volumes and applied it for evaluating K+ and Na+ cations impact on yeasts. We observed an inverse relationship between the maximal growth rate and cell volume that was responsive to K+/Na+ cationic interventions. We found that the addition of certain K+ concentration to CEN.PK cultures containing 1.0 M of Na+ increased the specific growth rate by four−fold with a parabolic shift in cell and vacuole volumes. An impairment of ethanol and acetate utilization in CEN.PK, acetate in W303, at increased cation concentrations implied that K+−Na+ interactions interceded over the metabolic pathways required for consumption of respiratory substrates. The addition of cations induced trade−off in glucose utilization but alleviated cellular aggregates formation in RT and K+−Na+ interactions increased beta−carotene yield by 60% compared with the reference. Comparison of cell and vacuole volumes in the exponential phase showed that volumes decreased the most for KM and least for RT in response to K+/Na+ cations. Noteworthy for the implication in aging research using yeasts, vacuole to cell volume ratio increased with the increase in cell volume for W303 and KM, but not for CEN.PK and RT strains.

Metabolism Control in 3D Printed Living Materials

“…This is a typical response to environmental stress in cell cultures. 38,39 Usually, one would expect a decreased cell size during ethanol-phase growth in suspension cultures. 40 We also observed a decrease in cell viability (93.54 %) after cultivation on ethanol as a carbon source, indicating cellular stress ( Figure S4B).…”