Molecular cloning, sequence analysis, and expression of the yeast alcohol acetyltransferase gene

Fujii, Toshio; Nagasawa, Naoshi; Iwamatsu, Akihiro; Bogaki, Takayuki; Tamai, Yoshitaka; Hamachi, Masaaki

doi:10.1128/aem.60.8.2786-2792.1994

Cited by 216 publications

(96 citation statements)

References 17 publications

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“…Evolution of isoamyl alcohol (A) and isobutanol (B) levels during fermentation of wort brewed with 100% Scarlett or 50% Scarlett and 50% of dark malt (Melanoidin, Cara-aroma and roasted malt). Properties of these wort samples are presented in Table VII. are the key enzymes involved in the biosynthesis of acetate esters 15,25,27 . Deletion and overexpression studies indicated that the ATF1 gene is responsible for the formation of both isoamyl acetate and ethyl acetate, whereas ATF2 mainly leads to isoamyl acetate 35 .…”

Section: Figmentioning

confidence: 99%

Impact of Dark Specialty Malts on Extract Composition and Wort Fermentation

Coghe

D'Hollander

Verachtert

et al. 2005

Journal of the Institute of Brewing

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Dark specialty malts are important ingredients for the production of several beer styles. These malts not only impart colour, flavour and antioxidative activity to wort and beer, they also affect the course of wort fermentations and the production of flavouractive yeast metabolites. The application of considerable levels of dark malt was found to lower the attenuation, mainly as a result of lower levels of fermentable sugars and amino acids in dark wort samples. In fact, from the darkest caramel malts and from roasted malts, practically no fermentable material can be hydrolysed by pilsner malt enzymes during mashing. Compared to wort brewed with 50% pilsner malt and 50% dark caramel malt or roasted malt, wort brewed with 100% pilsner malt contained nearly twice as much fermentable sugars and amino acids. Reduced levels of yeast nutrients also lowered the fermentation rate, ranging from 1.7°P/day for the reference pilsner wort of 9 EBC to 1.1°P/day for the darkest wort (890 EBC units), brewed with 50% roasted malt. This additionally indicates that lower attenuation values for dark wort are partially due to the inhibitory effects of Maillard compounds on yeast metabolism. The application of dark caramel or roasted malts further led to elevated levels of the vicinal diketones diacetyl and 2,3-pentanedione. Only large levels of roasted malt gave rise to two significant diacetyl peaks during fermentation. The level of ethyl acetate in beer was inversely related to colour, whereas the level of isoamyl acetate appeared to be affected by the use of roasted malt. With large levels of this malt type, negligible isoamyl acetate was generated during fermentation.

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Section: Figmentioning

confidence: 99%

Impact of Dark Specialty Malts on Extract Composition and Wort Fermentation

Coghe

D'Hollander

Verachtert

et al. 2005

Journal of the Institute of Brewing

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“…During the primary (alcoholic) fermentation of grape sugars, the wine yeast, Saccharomyces cerevisiae, produces ethanol, carbon dioxide and a number of byproducts, including esters, of which alcohol acetate and C 4 -C 10 fatty acid ethyl esters are found in the highest concentrations in wine and brandy Nykänen and Suomalainen, 1983;Schreier, 1979;Swiegers 642 M. Lilly et al flavour with a honey note) Fujii et al, 1994). These esters are synthesized in the yeast cells by alcohol acetyltransferases (AATases), using higher alcohols and acetyl-CoA as substrates.…”

Section: Introductionmentioning

confidence: 99%

The effect of increased yeast alcohol acetyltransferase and esterase activity on the flavour profiles of wine and distillates

Lilly

Bauer

Lambrechts

et al. 2006

Yeast

216

174

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The fruity odours of wine are largely derived from the synthesis of esters and higher alcohols during yeast fermentation. The ATF1-and ATF2-encoded alcohol acetyltransferases of S. cerevisiae are responsible for the synthesis of ethyl acetate and isoamyl acetate esters, while the EHT1-encoded ethanol hexanoyl transferase is responsible for synthesizing ethyl caproate. However, esters such as these might be degraded by the IAH1-encoded esterase. The objectives of this study were: (a) to overexpress the genes encoding ester-synthesizing and ester-degrading enzymes in wine yeast; (b) to prepare Colombard table wines and base wines for distillation using these modified strains; and (c) to analyse and compare the ester concentrations and aroma profiles of these wines and distillates. The overexpression of ATF1 significantly increased the concentrations of ethyl acetate, isoamyl acetate, 2-phenylethyl acetate and ethyl caproate, while the overexpression of ATF2 affected the concentrations of ethyl acetate and isoamyl acetate to a lesser degree. The overexpression of IAH1 resulted in a significant decrease in ethyl acetate, isoamyl acetate, hexyl acetate and 2-phenylethyl acetate. The overexpression of EHT1 resulted in a marked increase in ethyl caproate, ethyl caprylate and ethyl caprate. The flavour profile of the wines and distillates prepared using the modified strains were also significantly altered as indicated by formal sensory analysis. This study offers prospects for the development of wine yeast starter strains with optimized ester-producing capability that could assist winemakers in their effort to consistently produce wine and distillates such as brandy to definable flavour specifications and styles.

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“…However, the enzymes involved in ester synthesis have not been clearly identified. In the lactic acid bacteria Lactococcus lactis, esterase purification (Holland and Coolbear 1996;Chich et al 1997) and genome sequencing (Bolotin et al 2001) have revealed that this bacterium probably contains only one esterase and no lipase or an alcohol acetyltransferase homologous to those found in yeasts (Fuji et al 1994). The negative mutant for the main or unique lactococcal esterase constructed by Fernandez et al 2000) has lost its capacity to hydrolyse ethyl esters especially ethyl butanoate but there is no data about its capacity to synthesize them.…”

Section: Introductionmentioning

confidence: 99%

The EstA esterase is responsible for the main capacity of Lactococcus lactis to synthesize short chain fatty acid esters in vitro

et al. 2002

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Aims: Esters of short-chain fatty acids and alcohols participate significantly in the overall flavour of foods. The capacity of the lactic acid bacterium Lactococcus lactis to synthesize such esters is known even though the enzymes involved in the process are not well identified. The objective of our work is to determine whether the esterase is responsible for the whole capacity of L. lactis to synthesize esters in vitro. Methods and Results: A negative mutant for the esterase was constructed and its capacity to synthesize short chain fatty acid esters from different substrate couples was compared to that of the wild type. We observed that the esterase is responsible for the main ester synthesis activity of L. lactis in vitro. However, in the presence of some substrates, the esterase negative mutant still synthesizes low amounts of esters. Conclusions: In favourable environmental conditions, the L. lactis esterase is responsible for the main ester synthesizing activity, even though another pathway for ester synthesis probably exists. Significance and Impact of the Study: Since esters are potent aroma compounds, esterase is probably a key enzyme in the development of food flavour.

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Molecular cloning, sequence analysis, and expression of the yeast alcohol acetyltransferase gene

Cited by 216 publications

References 17 publications

Impact of Dark Specialty Malts on Extract Composition and Wort Fermentation

Impact of Dark Specialty Malts on Extract Composition and Wort Fermentation

The effect of increased yeast alcohol acetyltransferase and esterase activity on the flavour profiles of wine and distillates

The EstA esterase is responsible for the main capacity of Lactococcus lactis to synthesize short chain fatty acid esters in vitro

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