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We previously constructed a Saccharomyces cerevisiae carotenoid producer BL03-D-4 which produced much more carotenoid in YPM (modified YPD) media than YPD media. In this study, the impacts of nutritional components on carotenoid accumulation of BL03-D-4 were investigated. When using YPM media, the carotenoid yield was increased 10-fold compared to using the YPD media. To elucidate the hidden mechanism, a transcriptome analysis was performed and showed that 464 genes changed significantly in YPM media. Furthermore, inspired by the differential gene expression analysis which indicated that ADY2, HES1, and CUP1 showed the most remarkable changes, we found that the improvement of carotenoid accumulation in YPM media was mainly due to the copper ions, since supplementation of 0.08 mM CuSO4 in YPD media could increase carotenoid yield 9.2-fold. Reverse engineering of target genes was performed and carotenoid yield could be increased 6.4-fold in YPD media through overexpression of ACE1. The present study revealed for the first time the prominent promotion of carotenoid yield by copper ions in engineered S. cerevisiae and provided a new target ACE1 for genetic engineering of S. cerevisiae for the bioproduction of carotenoids.

We aimed to manipulate the metabolism of Saccharomyces cerevisiae to produce lactic acid and search for the potential influence of acid transport across the plasma membrane in this process. Saccharomyces cerevisiae W303-1 A is able to use l-lactic acid but its production in our laboratory has not previously been detected. When the l- LDH gene from Lactobacillus casei was expressed in S. cerevisiae W303-1 A and in the isogenic mutants jen1 ∆, ady2 ∆ and jen1 ∆ ady2∆, all strains were able to produce lactic acid, but higher titres were achieved in the mutant strains. In strains constitutively expressing both LDH and JEN1 or ADY2, a higher external lactic acid concentration was found when glucose was present in the medium, but when glucose was exhausted, its consumption was more pronounced. These results demonstrate that expression of monocarboxylate permeases influences lactic acid production. Ady2 has been previously characterized as an acetate permease but our results demonstrated its additional role in lactate uptake. Overall, we demonstrate that monocarboxylate transporters Jen1 and Ady2 are modulators of lactic acid production and may well be used to manipulate lactic acid export in yeast cells. [ABSTRACT FROM AUTHOR]

Abstract: The ability of cells to respond to changes in their environment is mediated by transcription factors that remodel chromatin and reprogram expression of specific subsets of genes. In Saccharomyces cerevisiae, changes in carbon source lead to gene induction by Adr1 and Cat8 that are known to require the upstream function of the Snf1 protein kinase, the central regulator of carbon metabolism, to exert their activating effect. How Snf1 facilitates transcription activation by Adr1 and Cat8 is not known. Here we show that under derepressing conditions, deletion of SNF1 abolishes the increase of histone H3 acetylation at the promoter of the glucose-repressed ADY2 gene, and as a consequence profoundly affects the chromatin structural alterations accompanying transcriptional activation. Adr1 and Cat8 are not required to regulate the acetylation switch and show only a partial influence on chromatin remodelling at this promoter, though their double deletion completely abolishes mRNA accumulation. Finally, we show that under derepressing conditions the recruitment of the histone acetyltransferase Gcn5 is abolished by SNF1 deletion, possibly explaining the lack of increased histone H3 acetylation and nucleosome remodelling. The results highlight a mechanism by which signalling to chromatin provides an essential permissive signal that is required for activation by glucose-responsive transcription factors. [Copyright &y& Elsevier]

We previously constructed a Saccharomyces cerevisiae carotenoid producer BL03-D-4 which produced much more carotenoid in YPM (modified YPD) media than YPD media. In this study, the impacts of nutritional components on carotenoid accumulation of BL03-D-4 were investigated. When using YPM media, the carotenoid yield was increased 10-fold compared to using the YPD media. To elucidate the hidden mechanism, a transcriptome analysis was performed and showed that 464 genes changed significantly in YPM media. Furthermore, inspired by the differential gene expression analysis which indicated that ADY2, HES1, and CUP1 showed the most remarkable changes, we found that the improvement of carotenoid accumulation in YPM media was mainly due to the copper ions, since supplementation of 0.08 mM CuSO4 in YPD media could increase carotenoid yield 9.2-fold. Reverse engineering of target genes was performed and carotenoid yield could be increased 6.4-fold in YPD media through overexpression of ACE1. The present study revealed for the first time the prominent promotion of carotenoid yield by copper ions in engineered S. cerevisiae and provided a new target ACE1 for genetic engineering of S. cerevisiae for the bioproduction of carotenoids. [ABSTRACT FROM AUTHOR]