Project description:Metabolic engineering of Saccharomyces cerevisiae for efficient monoterpenes production was mostly restricted by the limited tolerance to these chemicals. Understanding of the molecular mechanisms underlying the tolerance of S. cerevisiae to monoterpenes was essential for the de novo biosynthesis these chemicals in S. cerevisiae. In this study, commercial oligonucleotide microarray assays were performed to investigate the global response of S. cerevisiae to typical monoterpene D-limonene under transcriptional level. Yeast cell treated with sublethal dose of D-liomonene, gene change profiles were investigated at transcription level and the microarry data were also verified with quantitative real time PCR. D-limonene induced gene expression in Saccharomyces cerevisiae at early logarithmic phase was measured at 2 hours after exposure to doses of 0.02% (v/v) D-limonene. Three independent experiments were performed for each experiment (control or 2 hours).
Project description:A caffeine-resistant Saccharomyces cerevisiae mutant strain was obtained using an evolutionary engineering strategy based on successive batch cultivation at gradually increasing caffeine levels. The mutant strain Caf905-2 was selected at a caffeine concentration where its reference strain could not grow at all. Whole-genome transcriptomic analysis of Caf905-2 was performed with respect to its reference strain.
Project description:Metabolic engineering of Saccharomyces cerevisiae for efficient monoterpenes production was mostly restricted by the limited tolerance to these chemicals. Understanding of the molecular mechanisms underlying the tolerance of S. cerevisiae to monoterpenes was essential for the de novo biosynthesis these chemicals in S. cerevisiae. In this study, commercial oligonucleotide microarray assays were performed to investigate the global response of S. cerevisiae to typical monoterpene D-limonene under transcriptional level. Yeast cell treated with sublethal dose of D-liomonene, gene change profiles were investigated at transcription level and the microarry data were also verified with quantitative real time PCR.
Project description:The vanillin tolerance Saccharomyces cerevisiae was screened and compared intracellular ergosterol levels with several laboratory yeast strains, to study potential relationship between ergosterol contents and vanillin tolerance. S. cerevisiae NBRC1950 was selected as a vanillin tolerant strain. Its ergosterol contents were higher than those of laboratory strains. The results of DNA microarray and quantitative RT-PCR analysis showed that 5 genes involved in ergosterol biosynthesis (ERG28, HMG1, MCR1, ERG5 and ERG7) were up-regulated in NBRC 1950 compared with strain X2180, suggested that high expressions of genes involved in ergosterol biosynthesis may cause for the high ergosterol content in strain NBRC 1950. S. cerevisiae HX strain, which was a high ergosterol content strain derived from X2180, became more tolerant to vanillin compared with the parental strain. It is suggested that high ergosterol contents may be in part responsible for vanillin tolerance. These findings provide a biotechnological basis for the molecular engineering of S. cerevisiae with increased tolerance to vanillin.
Project description:The aim of present study is to understand the impact of xylose utilization on the Saccharomyces cerevisiae physiology after initial genetic engineering and in a strain with an improved xylose utilization phenotype.
Project description:Saccharomyces cerevisiae is an excellent microorganism for industrial succinic acid production, but high succinic acid concentration will inhibit the growth of Saccharomyces cerevisiae then reduce the production of succinic acid. Through analysis the transcriptomic data of Saccharomyces cerevisiae with different genetic backgrounds under different succinic acid stress, we hope to find the response mechanism of Saccharomyces cerevisiae to succinic acid.
Project description:Saccharomyces cerevisiae IMS0002 which, after metabolic and evolutionary engineering, ferments the pentose sugar arabinose. Glucose and arabinose-limited anaerobic chemostat cultures of IMS0002 and its non-evolved ancestor IMS0001 were subjected to transcriptome analysis to identify key genetic changes contributing to efficient arabinose utilization by strain IMS0002.
Project description:One of the essential or beneficial micronutrient for plants and animals is boron that is an ultra-trace element. Although boron can inhibit the growth of Saccharomyces cerevisiae around 80 mM, it is also a growth supplement. However, little information is currently available regarding the molecular mechanisms and essentiality of boron. In this paper, the approach was to generate S. cerevisiae mutants with high boron resistance by using evolutionary engineering strategy that was previously applied successfully. Boron-resistant S. cerevisiae mutants were obtained and their phenotypic and physiological characteristics were determined. In order to identify the molecular mechanisms implicated in boron resistance, the whole transcriptomes and genome sequence analysis of wild type and one of the most resistant mutants were compared.
Project description:During fermentation Saccharomyces yeast produces various aroma-active metabolites determining the different characteristics of aroma and taste in fermented beverages. Amino acid utilization by yeast during brewer´s wort fermentation is seen as linked to flavour profile. To better understand the relationship between the biosynthesis of aroma relevant metabolites and the importance of amino acids, DNA microarrays were performed for Saccharomyces cerevisiae strain S81 and Saccharomyces pastorianus var. carlsbergensis strain S23, respectively. Thereby, changes in transcription of genes were measured, which are associated with amino acid assimilation and its derived aroma-active compounds during fermentation.
Project description:Previously, it has been demonstrated that formate can be utilized by Saccharomyces cerevisiae as additional energy source using cells grown in a glucose-limited chemostat. Here, we investigated utilization of formaldehyde as co-substrate. Since endogenous formaldehyde dehydrogenase activities were insufficient to allow co-feeding of formaldehyde, the Hansenula polymorpha FLD1, encoding formaldehyde dehydrogenase, was introduced in S. cerevisiae. Chemostat cultivations revealed that formaldehyde was co-utilized with glucose, but the yield was lower than predicted. Moreover, formate was secreted by the cells. Upon co-expression of the H. polymorpha gene encoding formate dehydrogenase, FMD, the levels of secreted formate decreased, but the biomass yield was still lower than anticipated. Transcriptome comparisons of cells of the engineered FLD1/FMD-expressing S. cerevisiae strain grown with or without formaldehyde feed, suggested that the cells experienced biotin limitation, possibly due to inactivation of biotin by formaldehyde in the feed. When separate feeds were used for formaldehyde and biotin, the engineered S. cerevisiae strain was able to efficiently utilize formaldehyde as additional energy source. Keywords: response to additional compound