title: Differences between flocculating yeast and regular industrial yeast in transcription and metabolite profiling during ethanol fermentation.
abstract: Objectives:To improve ethanolic fermentation performance of self-flocculating yeast, difference between a flocculating yeast strain and a regular industrial yeast strain was analyzed by transcriptional and metabolic approaches.Results:The number of down-regulated (industrial yeast YIC10 vs. flocculating yeast GIM2.71) and up-regulated genes were 4503 and 228, respectively. It is the economic regulation for YIC10 that non-essential genes were down-regulated, and cells put more "energy" into growth and ethanol production. Hexose transport and phosphorylation were not the limiting-steps in ethanol fermentation for GIM2.71 compared to YIC10, whereas the reaction of 1,3-disphosphoglycerate to 3-phosphoglycerate, the decarboxylation of pyruvate to acetaldehyde and its subsequent reduction to ethanol were the most limiting steps. GIM2.71 had stronger stress response than non-flocculating yeast and much more carbohydrate was distributed to other bypass, such as glycerol, acetate and trehalose synthesis.Conclusions:Differences between flocculating yeast and regular industrial yeast in transcription and metabolite profiling will provide clues for improving the fermentation performance of GIM2.71.
authors.affiliation: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, 17 Chunhui Road, Laishan District, Yantai 264003, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Li
authors.affiliation: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, 17 Chunhui Road, Laishan District, Yantai 264003, China.
authors.forename: Xiaoning
authors.initials: X
authors.lastname: Wang
authors.affiliation: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, 17 Chunhui Road, Laishan District, Yantai 264003, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Jiao
authors.affiliation: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, 17 Chunhui Road, Laishan District, Yantai 264003, China.
authors.forename: Song
authors.initials: S
authors.lastname: Qin
keywords: Ethanol fermentation; Gene expression; Jerusalem artichoke; Metabolic analysis; Self-flocculating yeast