Improved fermentation performance of a lager yeast after repair of its AGT1 maltose and maltotriose transporter genes

Virve Vidgren, Anne Huuskonen, Hannele Virtanen, Laura Ruohonen, John Londesborough (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

35 Citations (Scopus)

Abstract

The use of more concentrated, so-called high-gravity and very-high-gravity (VHG) brewer's worts for the manufacture of beer has economic and environmental advantages. However, many current strains of brewer's yeasts ferment VHG worts slowly and incompletely, leaving undesirably large amounts of maltose and especially maltotriose in the final beers. α-Glucosides are transported into Saccharomyces yeasts by several transporters, including Agt1, which is a good carrier of both maltose and maltotriose. The AGT1 genes of brewer's ale yeast strains encode functional transporters, but the AGT1 genes of the lager strains studied contain a premature stop codon and do not encode functional transporters. In the present work, one or more copies of the AGT1 gene of a lager strain were repaired with DNA sequence from an ale strain and put under the control of a constitutive promoter. Compared to the untransformed strain, the transformants with repaired AGT1 had higher maltose transport activity, especially after growth on glucose (which represses endogenous α-glucoside transporter genes) and higher ratios of maltotriose transport activity to maltose transport activity. They fermented VHG (24° Plato) wort faster and more completely, producing beers containing more ethanol and less residual maltose and maltotriose. The growth and sedimentation behaviors of the transformants were similar to those of the untransformed strain, as were the profiles of yeast-derived volatile aroma compounds in the beers.
Original languageEnglish
Pages (from-to)2333-2345
Number of pages13
JournalApplied and Environmental Microbiology
Volume75
Issue number8
DOIs
Publication statusPublished - 2009
MoE publication typeA1 Journal article-refereed

Fingerprint

maltotriose
brewers yeast
Maltose
Hypergravity
maltose
repair
Fermentation
fermentation
yeast
transporters
Yeasts
gravity
gene
beers
Genes
Glucosides
genes
Saccharomyces cerevisiae
yeasts
glucosides

Keywords

  • beer, fermentation
  • brewing fermentation
  • fermentation
  • brewer's yeast
  • lager yeasts
  • yeasts

Cite this

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title = "Improved fermentation performance of a lager yeast after repair of its AGT1 maltose and maltotriose transporter genes",
abstract = "The use of more concentrated, so-called high-gravity and very-high-gravity (VHG) brewer's worts for the manufacture of beer has economic and environmental advantages. However, many current strains of brewer's yeasts ferment VHG worts slowly and incompletely, leaving undesirably large amounts of maltose and especially maltotriose in the final beers. α-Glucosides are transported into Saccharomyces yeasts by several transporters, including Agt1, which is a good carrier of both maltose and maltotriose. The AGT1 genes of brewer's ale yeast strains encode functional transporters, but the AGT1 genes of the lager strains studied contain a premature stop codon and do not encode functional transporters. In the present work, one or more copies of the AGT1 gene of a lager strain were repaired with DNA sequence from an ale strain and put under the control of a constitutive promoter. Compared to the untransformed strain, the transformants with repaired AGT1 had higher maltose transport activity, especially after growth on glucose (which represses endogenous α-glucoside transporter genes) and higher ratios of maltotriose transport activity to maltose transport activity. They fermented VHG (24° Plato) wort faster and more completely, producing beers containing more ethanol and less residual maltose and maltotriose. The growth and sedimentation behaviors of the transformants were similar to those of the untransformed strain, as were the profiles of yeast-derived volatile aroma compounds in the beers.",
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author = "Virve Vidgren and Anne Huuskonen and Hannele Virtanen and Laura Ruohonen and John Londesborough",
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Improved fermentation performance of a lager yeast after repair of its AGT1 maltose and maltotriose transporter genes. / Vidgren, Virve; Huuskonen, Anne; Virtanen, Hannele; Ruohonen, Laura; Londesborough, John (Corresponding Author).

In: Applied and Environmental Microbiology, Vol. 75, No. 8, 2009, p. 2333-2345.

Research output: Contribution to journalArticleScientificpeer-review

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T1 - Improved fermentation performance of a lager yeast after repair of its AGT1 maltose and maltotriose transporter genes

AU - Vidgren, Virve

AU - Huuskonen, Anne

AU - Virtanen, Hannele

AU - Ruohonen, Laura

AU - Londesborough, John

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N2 - The use of more concentrated, so-called high-gravity and very-high-gravity (VHG) brewer's worts for the manufacture of beer has economic and environmental advantages. However, many current strains of brewer's yeasts ferment VHG worts slowly and incompletely, leaving undesirably large amounts of maltose and especially maltotriose in the final beers. α-Glucosides are transported into Saccharomyces yeasts by several transporters, including Agt1, which is a good carrier of both maltose and maltotriose. The AGT1 genes of brewer's ale yeast strains encode functional transporters, but the AGT1 genes of the lager strains studied contain a premature stop codon and do not encode functional transporters. In the present work, one or more copies of the AGT1 gene of a lager strain were repaired with DNA sequence from an ale strain and put under the control of a constitutive promoter. Compared to the untransformed strain, the transformants with repaired AGT1 had higher maltose transport activity, especially after growth on glucose (which represses endogenous α-glucoside transporter genes) and higher ratios of maltotriose transport activity to maltose transport activity. They fermented VHG (24° Plato) wort faster and more completely, producing beers containing more ethanol and less residual maltose and maltotriose. The growth and sedimentation behaviors of the transformants were similar to those of the untransformed strain, as were the profiles of yeast-derived volatile aroma compounds in the beers.

AB - The use of more concentrated, so-called high-gravity and very-high-gravity (VHG) brewer's worts for the manufacture of beer has economic and environmental advantages. However, many current strains of brewer's yeasts ferment VHG worts slowly and incompletely, leaving undesirably large amounts of maltose and especially maltotriose in the final beers. α-Glucosides are transported into Saccharomyces yeasts by several transporters, including Agt1, which is a good carrier of both maltose and maltotriose. The AGT1 genes of brewer's ale yeast strains encode functional transporters, but the AGT1 genes of the lager strains studied contain a premature stop codon and do not encode functional transporters. In the present work, one or more copies of the AGT1 gene of a lager strain were repaired with DNA sequence from an ale strain and put under the control of a constitutive promoter. Compared to the untransformed strain, the transformants with repaired AGT1 had higher maltose transport activity, especially after growth on glucose (which represses endogenous α-glucoside transporter genes) and higher ratios of maltotriose transport activity to maltose transport activity. They fermented VHG (24° Plato) wort faster and more completely, producing beers containing more ethanol and less residual maltose and maltotriose. The growth and sedimentation behaviors of the transformants were similar to those of the untransformed strain, as were the profiles of yeast-derived volatile aroma compounds in the beers.

KW - beer, fermentation

KW - brewing fermentation

KW - fermentation

KW - brewer's yeast

KW - lager yeasts

KW - yeasts

U2 - 10.1128/AEM.01558-08

DO - 10.1128/AEM.01558-08

M3 - Article

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JO - Applied and Environmental Microbiology

JF - Applied and Environmental Microbiology

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ER -