A selection of Saccharomyces cerevisiae promoters for biotechnological applications aiming at the use of synthetic glycerol medium

Glycerol offers several advantages as a substrate for biotechnological applications. An important step towards using the popular production host Saccharomyces cerevisiae for glycerol-based bioprocesses have been recent studies in which commonly used S. cerevisiae strains were engineered to grow in synthetic medium containing glycerol as the sole carbon source. In order to boost extensive S. cerevisiae metabolic engineering incentives aiming at the use of glycerol, we realized that promoters with predictable expression levels in synthetic glycerol medium were required. In the current study, we used transcriptome analysis and a yECitrine-based fluorescence reporter assay to select and characterize useful 25 promoters for driving expression of target genes in S. cerevisiae under the given conditions. The promoters of the genes ALD4 and ADH2 showed 4.2- and 3-fold higher activities compared to the well-known strong TEF1 promoter. Moreover, the collection contains promoters with graded activities in synthetic glycerol medium and different degrees of glucose repression. To demonstrate the general applicability of the promoter collection, we successfully used a subset of the characterized promoters with graded activities in order to optimize growth on glycerol in an engineered derivative of CEN.PK, in which glycerol catabolism exclusively occurs via a non-native DHA pathway. Examine one sample of S. cerevisiae's transcriptome during exponential growth in synthetic glycerol medium.