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Ethanol-induced yeast flocculation directed by the promoter of TPS1 encoding trehalose-6-phosphate synthase 1 for efficient ethanol production

Paper ID Volume ID Publish Year Pages File Format Full-Text
31623 44825 2012 8 PDF Available
Title
Ethanol-induced yeast flocculation directed by the promoter of TPS1 encoding trehalose-6-phosphate synthase 1 for efficient ethanol production
Abstract

Yeast flocculation is an important trait in the brewing industry as well as in ethanol production, through which biomass can be recovered by cost-effective sedimentation. However, mass transfer limitation may affect yeast growth and ethanol fermentation if the flocculation occurs earlier before fermentation is completed. In this article, a novel type of cell-cell flocculation induced by trehalose-6-phosphate synthase 1 (TPS1) promoter was presented. The linear cassette HO–PTPS1–FLO1SPSC01–KanMX4–HO was constructed to transform the non-flocculating industrial yeast S. cerevisiae 4126 by chromosome integration to obtain a new flocculating yeast strain, ZLH01, whose flocculation was induced by ethanol produced during fermentation. The experimental results illustrated that flocculation of ZLH01 was triggered by 3% (v/v) ethanol and enhanced as ethanol concentration increased till complete flocculation was achieved at ethanol concentration of 8% (v/v). Real time PCR analysis confirmed that the expression of FLO1SPSC01 was dependent on ethanol concentration. The growth and ethanol fermentation of ZLH01 were improved significantly, compared with the constitutive flocculating yeast BHL01 engineered with the same FLO gene but directed by the constitutive 3-phosphoglycerate kinase promoter PGK1, particularly under high temperature conditions. These characteristics make the engineered yeast more suitable for ethanol production from industrial substrates under high gravity and temperature conditions. In addition, this strategy offers advantage in inducing differential expression of other genes for metabolic engineering applications of S. cerevisiae.

.► The promoter of TPS1 encoding trehalose-6-phosphate synthase 1 responses to ethanol. ► The flocculation of yeast induced by ethanol exhibits good fermentation performance. ► TPS1-directed differential gene expression is a useful strategy.

Keywords
Saccharomyces cerevisiae; Ethanol fermentation; Induced flocculation; FLO1SPSC01; TPS1 promoter
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Ethanol-induced yeast flocculation directed by the promoter of TPS1 encoding trehalose-6-phosphate synthase 1 for efficient ethanol production
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Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 14, Issue 1, January 2012, Pages 1–8
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us