Stl1 transporter mediating the uptake of glycerol is not a weak point of Saccharomyces kudriavzevii's low osmotolerance

This report studiedS. kudriavzevii relative osmosensitivity and its capacity for active glycerol uptake. The results obtained (on the activity and physiological function ofS. kudriavzevii glycerol transporter) may contribute to a further engineering of this species aiming to improve its osmotolerance. AbstractSaccharomyces kudriavzevii is a nonconventional and rather osmosensitive yeast with a high potential of use in fermentation processes. To elucidate the basis of its relative osmosensitivity, the role of theSTL1 gene encoding a putative glycerol uptake system was studied. Under higher osmotic pressure, the addition of a low amount of glycerol to the growth medium improved the growth ofS. kudriavzevii and the expression of theSTL1 gene was highly induced. Deletion of this gene decreased the strain's ability to grow in the presence of higher concentrations of salts and other solutes. Moreover, the mutant had a disturbed homeostasis of intracellular pH. Expression of theSkSTL1 gene inSaccharomyces cerevisiae complemented the osmosensitivity of theS. cerevisiae hog1 Δ stl1Δ mutant, and the gene's tagging with GFP localized its product to the plasma membrane. Altogether, a deficiency in glycerol uptake did not seem to be the reason forS. kudriavzevii's low osmotolerance; its Stl1 transporter properly contributes to the regulation of intracellular pH and is crucial to its survival of osmotic stress.Significance and Impact of the StudyAn increasing demand for food products wit...
Source: Letters in Applied Microbiology - Category: Microbiology Authors: Tags: Original Article Source Type: research