Project description:Furfural, phenol and acetic acid, generated during cellulosic material pretreatment, are the representative inhibitors to yeast used for ethanol production. The responses to these inhibitors in industrial yeast and the corresponding adapted strains were analyzed. Experiment Overall Design: We analyzed the transient response to inhibitors and the different transcriptions in industrial yeast and furfural-, phenol-, and acetic acid-adapted strains. Industrial yeast and the adapted strains were collected at 20 minutes after inhibitor addition. The reference samples for industrial yeast and adapted strains were collected at the same time without inhibitor addition. 2 replicates for each strain/treatment were analyzed.
Project description:Furfural, phenol and acetic acid, generated during the cellulosic material pretreatment, are the representative inhbitors to yeast used for ethanol production. The responses to multi-inhbitors in industrial yeast and the tolerant strain were analyzed. We analyzed the transcriptome of the parental and tolerant strains in the presence of multi-inhibitors. Parental and tolerant strains were collected at the exponential stage in the presence of multi-inhibitors. The reference samples for industrial yeast and adapted strains were collected at the same growth stage in the absence of inhibitors.
Project description:Furfural, phenol and acetic acid, generated during cellulosic material pretreatment, are the representative inhibitors to yeast used for ethanol production. The responses to these inhibitors in industrial yeast and the corresponding adapted strains were analyzed.
Project description:The environmental stresses and inhibitors encounted by Saccharomyces cerevisiae strains are main limiting factors in bioethanol fermentation. Investigation of the molecular mechanisms underlying the stresses-related phenotypes diversities within and between S. cerevisiae populations could guide the construction of yeast strains with improved stresses tolerance and fermentation performances. Here, we explored the genetic characteristics of the bioethanol S. cerevisiae strains, and elucidated the genetic variations correlated with its advantaged traits (higher ethanol yield under sever conditions and better tolerance to multiple stresses compared to an S288c derived laboratory strain BYZ1). Firstly, pulse-field gel electrophoresis combined with array-comparative genomic hybridization was used to compare the genome structure of industrial strains and the laboratory strain BYZ1.
Project description:Furfural, phenol and acetic acid, generated during the cellulosic material pretreatment, are the representative inhbitors to yeast used for ethanol production. The responses to multi-inhbitors in industrial yeast and the tolerant strain were analyzed. We analyzed the transcriptome of the parental and tolerant strains in the presence of multi-inhibitors.
Project description:Laboratory strains of Saccharmoyces cerevisiae have been widely used as a model for studying eukaryotic cells and mapping the molecular mechanisms of many different human diseases. Industrial wine yeasts, on the other hand, have been selected over hundreds of years on the basis of their adaptation to stringent environmental conditions and the organoleptic properties they confer to wine. Here, we applied a two-factor design to study the response of a standard laboratory strain, CEN.PK.113-7D, and an industrial wine yeast-strain, EC1118, to growth temperature at 15°C and 30°C under 12 nitrogen-limited, anaerobic steady-state chemostat cultures. Physiological characterization revealed that growth temperature strongly impacted biomass yields in both strains. Moreover, we observed that the wine yeast is better adapted to mobilizing resources for biomass and that the laboratory yeast exhibited higher fermentation rates. To elucidate mechanistic differences controlling the growth temperature response and underlying adaptive mechanisms between strains, DNA microarrays and targeted metabolome analysis were used. We identified 1007 temperature dependent genes and 473 strain dependent genes. The transcriptional response was used to identify highly correlated subnetworks of significantly changing genes in metabolism. We show that temperature differences most strongly affect nitrogen metabolism and the heat shock response. Lack of STRE mediated gene induction, coupled with reduced trehalose levels, indicates a decreased general stress response at 15°C relative to 30°C. Between strains, differential responses are centred around sugar uptake, nitrogen metabolism and expression of genes related to organoleptic properties. Our study provides global insight into how growth temperature exerts a differential physiological and transcriptional response in laboratory and wine strains of S. cerevisiae.
Project description:To gain deep understanding of yeast cell response to heat stress, multiple laboratory strains have been intensively studied by genome-wide expression analysis for mechanistic dissection of classical heat shock response. However, robust industrial strains of S. cerevisiae have hardly been explored in global analysis for elucidating the mechanism of thermotolerant response (TR) during fermentation. Herein, we employed DIA/SWATH–based proteomic workflows to characterize proteome remodeling of an industrial strain ScY01 responding to prolonged thermal stress or transient heat shock.
Project description:In the search for renewable sources of energy, bioethanol stands out as a benchmark biofuel because its production is based on a proven technological platform. Bioethanol is produced mainly from the fermentation of carbohydrates derived from agricultural feedstocks by the yeast Saccharomyces cerevisiae. One of the most widely adopted strains is PE-2, a heterothallic diploid naturally adapted to the sugar cane fermentation process used in Brazil. Here we report the molecular genetic analysis of a PE-2 derived diploid (JAY270), and the complete genome sequence of a haploid derivative (JAY291). The JAY270 genome is highly heterozygous (~2 SNPs per kilobase), and has several structural polymorphisms between homologous chromosomes. These chromosomal rearrangements are confined to the peripheral regions of the chromosomes, and appear to reflect ectopic homologous recombination between repetitive DNA sequences. Despite the complex karyotype of JAY270, this diploid, when sporulated, had a high frequency of viable spores (~93%). Crosses of haploids derived from JAY270 to a haploid of the unrelated laboratory strain S288c also resulted in diploids that had good spore viability (75-95%). Thus, the rearrangements that exist near the ends of chromosomes do not impair meiosis and spore viability, as they do not span regions that contain essential genes. This observation is consistent with a model in which the peripheral regions of chromosomes represent plastic domains of the genome that are free to recombine ectopically and experiment with alternative structures that may be associated with a fitness benefit. We also explore features of the JAY270 and JAY291 genomes that help explain their high adaptation to industrial environments, exhibiting desirable phenotypes such as high cell mass production and fermentation kinetics, high temperature growth and oxidative stress tolerance. The genomic manipulation of such strains could enable the creation a new generation of industrial organisms, ideally suited for use as delivery vehicles for future bioenergy technologies.