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Acetate Ester
The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Dongguang Xiao – One of the best experts on this subject based on the ideXlab platform.
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Modulating Acetate Ester and higher alcohol production in Saccharomyces cerevisiae through the cofactor engineering
Journal of industrial microbiology & biotechnology, 2019Co-Authors: Kun-qiang Hong, Dongguang Xiao, Sheng-sheng Dong, Dong JianAbstract:Flavor production by Esters or by higher alcohols play a key role in the sensorial quality of fermented alcoholic beverages. In Saccharomyces cerevisiae cells, the syntheses of Esters and higher alcohols are considerably influenced by intracellular CoA levels catalyzed by pantothenate kinase. In this work, we examined the effects of cofactor CoA and acetyl-CoA synthesis on the metabolism of Esters and higher alcohols. Strains 12α−BAP2 and 12α+ATF1 where generated by deleting and overexpressing BAP2 (encoded branched-chain aminamino acid permease) and ATF1 (encoded alcohol acetyl transferases), respectively, in the parent 12α strains. Then, 12α−BAP2+CAB1 and 12α−BAP2+CAB3 strains were obtained by overexpressing CAB1 (encoded pantothenate kinase Cab1) and CAB3 (encoded pantothenate kinase Cab3) in the 12α−BAP2 strain, and 12α−BAP2+CAB1+ATF1 and 12α−BAP2+CAB3+ATF1 were generated by overexpressing ATF1 in the pantothenate kinase overexpression strains. The Acetate Ester level in 12α−BAP2 was slightly changed relative to that in the control strain 12α, whereas the Acetate Ester levels in 12α−BAP2+CAB1, 12α−BAP2+CAB3, 12α−BAP2+CAB1+ATF1, and 12α−BAP2+CAB3+ATF1 were distinctly increased (44–118% for ethyl Acetate and 18–57% for isoamyl Acetate). The levels of n-propanol, methyl-1-butanol, isopentanol, isobutanol, and phenethylol levels were changed and varied among the six engineered strains. The levels of Acetate Esters and higher alcohols can be modulated by changing the CoA and acetyl-CoA levels. The method proposed in this work supplies a practical means of breeding yeast strains by modulating Acetate Ester and higher alcohol production.
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PGK1 Promoter Library for the Regulation of Acetate Ester Production in Saccharomyces cerevisiae during Chinese Baijiu Fermentation.
Journal of agricultural and food chemistry, 2018Co-Authors: Dan-yao Cui, Cuiying Zhang, Yu Zhang, Dongguang XiaoAbstract:Appropriate concentrations and proportion of Acetate Esters and higher alcohols improve the quality of Chinese Baijiu. To regulate the concentrations of Acetate Esters in Chinese Baijiu, we constructed a PGK1 promoter library through error-prone PCR. Then, we used an enhanced green fluorescent protein as a reporter to characterize the activities of PGK1p mutants. The PGK1p library contained 28 PGK1p mutants and spanned an activity that ranged between 0.1% and 141% of wild-type PGK1p. Seven PGK1p mutants were characterized by an additional reporter β-galactosidase and then used for the overexpression of ATF1 with BAT2 deletion in Saccharomyces cerevisiae a45. The production of ethyl Acetate in strains A8, A17, A18, A27, A22, A25, A28, and AWT were 1.66-, 3.09-, 10.59-, 13.07-, 15.99-, 22.67-, 24.06-, and 27.22-fold higher than that of the parental strain. The results on alcohol acetyltransferase (AATase) activity showed that the PGK1p library precisely controlled ATF1 expression and regulated the Acetate Esters production.
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Overexpression of different alcohol acetyltransferase genes with BAT2 deletion in Saccharomyces cerevisiae affects Acetate Esters and higher alcohols
European Food Research and Technology, 2017Co-Authors: Dan-yao Cui, Cuiying Zhang, Yefu Chen, Jian-hui Wang, Xiao-er Liu, Zheng Zhou, Dongguang XiaoAbstract:Acetate Esters and higher alcohols significantly determine the flavor profiles of Chinese Baijiu (Chinese liquor). The aminotransferase encoded by BAT2 and alcohol acetyltransferases encoded by ATF1, ATF2, and Lg-ATF1 are involved in the production of branched-chain alcohols and synthesis of Acetate Esters, respectively. In this study, the effects of ATF1, ATF2, and Lg-ATF1 overexpressions with BAT2 deletion were explored in Chinese Baijiu yeast. The differences among these effects were also investigated. Results showed that the productions of Acetate Esters by mutant overexpressing ATF1 with BAT2 deletion and that overexpressing ATF2 with BAT2 deletion were 1353.45 and 73.40 mg/L, respectively, which were 43.16- and 2.34-fold higher than that by the original strain. Compared with mutant overexpressing ATF2 with BAT2 deletion, mutant overexpressing ATF1 with BAT2 deletion exhibited 48.17% decreased higher alcohol productivity. The production of higher alcohols in mutant overexpressing ATF2 with BAT2 deletion was similar to that in the BAT2 deletion mutant. Furthermore, no significant difference was observed between the BAT2 deletion mutant and the mutant overexpressing Lg-ATF1 with BAT2 deletion in terms of Acetate Ester and higher alcohol production. The mutants that have varying capacities for Acetate Ester and higher alcohol production can be potentially developed and applied.
Kevin J. Verstrepen – One of the best experts on this subject based on the ideXlab platform.
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Tuning chocolate flavor through development of thermotolerant Saccharomyces cerevisiae starter cultures with increased Acetate Ester production
Applied and environmental microbiology, 2015Co-Authors: Esther Meersman, Jan Steensels, Nore Struyf, Tinneke Paulus, Veerle Saels, Melissa Mathawan, Leen Allegaert, Gino Vrancken, Kevin J. VerstrepenAbstract:Microbial starter cultures have extensively been used to enhance the consistency and efficiency of industrial fermentations. Despite the advantages of such controlled fermentations, the fermentation involved in the production of chocolate is still a spontaneous process that relies on the natural microbiota at cocoa farms. However, recent studies indicate that certain thermotolerant Saccharomyces cerevisiae cultures can be used as starter cultures for cocoa pulp fermentation. In this study, we investigate the potential of specifically developed starter cultures to modulate chocolate aroma. Specifically, we developed several new S. cerevisiae hybrids that combine thermotolerance and efficient cocoa pulp fermentation with a high production of volatile flavor-active Esters. In addition, we investigated the potential of two strains of two non-Saccharomyces species that produce very large amounts of fruity Esters (Pichia kluyveri and Cyberlindnera fabianii) to modulate chocolate aroma. Gas chromatography-mass spectrometry (GC-MS) analysis of the cocoa liquor revealed an increased concentration of various flavor-active Esters and a decrease in spoilage-related off-flavors in batches inoculated with S. cerevisiae starter cultures and, to a lesser extent, in batches inoculated with P. kluyveri and Cyb. fabianii. Additionally, GC-MS analysis of chocolate samples revealed that while most short-chain Esters evaporated during conching, longer and more-fat-soluble ethyl and Acetate Esters, such as ethyl octanoate, phenylethyl Acetate, ethyl phenylAcetate, ethyl decanoate, and ethyl dodecanoate, remained almost unaffected. Sensory analysis by an expert panel confirmed significant differences in the aromas of chocolates produced with different starter cultures. Together, these results show that the selection of different yeast cultures opens novel avenues for modulating chocolate flavor.
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the fungal aroma gene atf1 promotes dispersal of yeast cells through insect vectors
Cell Reports, 2014Co-Authors: Joaquin F Christiaens, Luis M Franco, Tanne L Cools, Luc De Meester, Jan Michiels, Tom Wenseleers, Bassem A Hassan, Emre Yaksi, Kevin J. VerstrepenAbstract:Summary Yeast cells produce various volatile metabolites that are key contributors to the pleasing fruity and flowery aroma of fermented beverages. Several of these fruity metabolites, including isoamyl Acetate and ethyl Acetate, are produced by a dedicated enzyme, the alcohol acetyl transferase Atf1. However, despite much research, the physiological role of Acetate Ester formation in yeast remains unknown. Using a combination of molecular biology, neurobiology, and behavioral tests, we demonstrate that deletion of ATF1 alters the olfactory response in the antennal lobe of fruit flies that feed on yeast cells. The flies are much less attracted to the mutant yeast cells, and this in turn results in reduced dispersal of the mutant yeast cells by the flies. Together, our results uncover the molecular details of an intriguing aroma-based communication and mutualism between microbes and their insect vectors. Similar mechanisms may exist in other microbes, including microbes on flowering plants and pathogens.
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Production and biological function of volatile Esters in Saccharomyces cerevisiae
Microbial biotechnology, 2009Co-Authors: Sofie Saerens, Kevin J. Verstrepen, Freddy R. Delvaux, Johan M. TheveleinAbstract:The need to understand and control Ester synthesis is driven by the fact that Esters play a key role in the sensorial quality of fermented alcoholic beverages like beer, wine and sake. As Esters are synthesized in yeast via several complex metabolic pathways, there is a need to gain a clear understanding of Ester metabolism and its regulation. The individual genes involved, their functions and regulatory mechanisms have to be identified. In alcoholic beverages, there are two important groups of Esters: the Acetate Esters and the medium-chain fatty acid (MCFA) ethyl Esters. For Acetate Ester synthesis, the genes involved have already been cloned and characterized. Also the biochemical pathways and the regulation of Acetate Ester synthesis are well defined. With respect to the molecular basis of MCFA ethyl Ester synthesis, however, significant progress has only recently been made. Next to the characterization of the biochemical pathways and regulation of Ester synthesis, a new and more important question arises: what is the advantage for yeast to produce these Esters? Several hypotheses have been proposed in the past, but none was satisfactorily. This paper reviews the current hypotheses of Ester synthesis in yeast in relation to the complex regulation of the alcohol acetyl transferases and the different factors that allow Ester formation to be controlled during fermentation.
Pralay Das – One of the best experts on this subject based on the ideXlab platform.
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supported palladium nanoparticles as switchable catalyst for aldehyde conjugate s and Acetate Ester syntheses from alcohols
New Journal of Chemistry, 2017Co-Authors: Pralay Das, Dhananjay Bhattacherjee, Vandna Thakur, Sandeep Kumar, Abha ChaudharyAbstract:Polymer-supported Pd(0) (Pd@PS) nanoparticles (NPs) were explored as a switchable catalyst for oxidative aldehyde conjugate/s (AC/s) and Acetate Esters (AEs) syntheses from alcohols. Using the same substrates, the catalyst in the presence of oxygen and K2CO3 participated in AC/s synthesis, and in the presence of traces of air and NaOtBu, unusual AEs products were obtained.
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Supported palladium nanoparticles as switchable catalyst for aldehyde conjugate/s and Acetate Ester syntheses from alcohols
New Journal of Chemistry, 2017Co-Authors: Sandeep Kumar, Dhananjay Bhattacherjee, Vandna Thakur, Abha Chaudhary, Bandna, Pralay DasAbstract:Polymer-supported Pd(0) (Pd@PS) nanoparticles (NPs) were explored as a switchable catalyst for oxidative aldehyde conjugate/s (AC/s) and Acetate Esters (AEs) syntheses from alcohols. Using the same substrates, the catalyst in the presence of oxygen and K2CO3 participated in AC/s synthesis, and in the presence of traces of air and NaOtBu, unusual AEs products were obtained.
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Oxidative “reverse-Esterification” of ethanol with benzyl/alkyl alcohols or aldehydes catalyzed by supported rhodium nanoparticles
Green Chemistry, 2016Co-Authors: Nitul Ranjan Guha, Saurabh Sharma, Dhananjay Bhattacherjee, Vandna Thakur, Richa Bharti, C. Bal Reddy, Pralay DasAbstract:A very unusual role of polystyrene stabilized rhodium (Rh@PS) nanoparticles as a supported catalyst is described for “reverse-Esterification” of ethanol with benzyl/alkyl alcohols or aldehydes. Faster and selective oxidoxidation of ethanol to acetaldehyde and H2 under Rh@PS catalyzed conditions which restricted further oxidation of benzyl/alkyl alcohols and their in situ reaction gave the corresponding Acetate Esters following the dehydrogenative-coupling approach. A hitherto redox dehydrogenative-coupling of ethanol and aldehydes has also been explored for the same Acetate Ester synthesis under Rh@PS catalyzed conditions.
Cuiying Zhang – One of the best experts on this subject based on the ideXlab platform.
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PGK1 Promoter Library for the Regulation of Acetate Ester Production in Saccharomyces cerevisiae during Chinese Baijiu Fermentation.
Journal of agricultural and food chemistry, 2018Co-Authors: Dan-yao Cui, Cuiying Zhang, Yu Zhang, Dongguang XiaoAbstract:Appropriate concentrations and proportion of Acetate Esters and higher alcohols improve the quality of Chinese Baijiu. To regulate the concentrations of Acetate Esters in Chinese Baijiu, we constructed a PGK1 promoter library through error-prone PCR. Then, we used an enhanced green fluorescent protein as a reporter to characterize the activities of PGK1p mutants. The PGK1p library contained 28 PGK1p mutants and spanned an activity that ranged between 0.1% and 141% of wild-type PGK1p. Seven PGK1p mutants were characterized by an additional reporter β-galactosidase and then used for the overexpression of ATF1 with BAT2 deletion in Saccharomyces cerevisiae a45. The production of ethyl Acetate in strains A8, A17, A18, A27, A22, A25, A28, and AWT were 1.66-, 3.09-, 10.59-, 13.07-, 15.99-, 22.67-, 24.06-, and 27.22-fold higher than that of the parental strain. The results on alcohol acetyltransferase (AATase) activity showed that the PGK1p library precisely controlled ATF1 expression and regulated the Acetate Esters production.
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Overexpression of different alcohol acetyltransferase genes with BAT2 deletion in Saccharomyces cerevisiae affects Acetate Esters and higher alcohols
European Food Research and Technology, 2017Co-Authors: Dan-yao Cui, Cuiying Zhang, Yefu Chen, Jian-hui Wang, Xiao-er Liu, Zheng Zhou, Dongguang XiaoAbstract:Acetate Esters and higher alcohols significantly determine the flavor profiles of Chinese Baijiu (Chinese liquor). The aminotransferase encoded by BAT2 and alcohol acetyltransferases encoded by ATF1, ATF2, and Lg-ATF1 are involved in the production of branched-chain alcohols and synthesis of Acetate Esters, respectively. In this study, the effects of ATF1, ATF2, and Lg-ATF1 overexpressions with BAT2 deletion were explored in Chinese Baijiu yeast. The differences among these effects were also investigated. Results showed that the productions of Acetate Esters by mutant overexpressing ATF1 with BAT2 deletion and that overexpressing ATF2 with BAT2 deletion were 1353.45 and 73.40 mg/L, respectively, which were 43.16- and 2.34-fold higher than that by the original strain. Compared with mutant overexpressing ATF2 with BAT2 deletion, mutant overexpressing ATF1 with BAT2 deletion exhibited 48.17% decreased higher alcohol productivity. The production of higher alcohols in mutant overexpressing ATF2 with BAT2 deletion was similar to that in the BAT2 deletion mutant. Furthermore, no significant difference was observed between the BAT2 deletion mutant and the mutant overexpressing Lg-ATF1 with BAT2 deletion in terms of Acetate Ester and higher alcohol production. The mutants that have varying capacities for Acetate Ester and higher alcohol production can be potentially developed and applied.
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Acetate Ester production by Chinese yellow rice wine yeast overexpressing the alcohol acetyltransferase-encoding gene ATF2.
Genetics and molecular research : GMR, 2014Co-Authors: Jianwei Zhang, Cuiying Zhang, Longhai Dai, Xuewu Guo, Dongguang XiaoAbstract:Acetate Ester, which are produced by fermenting yeast cells in an enzyme-catalyzed intracellular reaction, are responsible for the fruity character of fermented alcoholic beverages such as Chinese yellow rice wine. Alcohol acetyltransferase (AATase) is currently believed to be the key enzyme responsible for the production of Acetate Ester. In order to determine the precise role of the ATF2 gene in Acetate Ester production, an ATF2 gene encoding a type of AATase was overexpressed and the ability of the mutant to form Acetate Esters (including ethyl Acetate, isoamyl Acetate, and isobutyl Acetate) was investigated. The results showed that after 5 days of fermentation, the concentrations of ethyl Acetate, isoamyl Acetate, and isobutyl Acetate in yellow rice wines fermented with EY2 (pUC-PIA2K) increased to 137.79 mg/L (an approximate 4.9-fold increase relative to the parent cell RY1), 26.68 mg/L, and 7.60 mg/L, respectively. This study confirms that the ATF2 gene plays an important role in the production of Acetate Ester production during Chinese yellow rice wine fermentation, thereby offering prospects for the development of yellow rice wine yeast starter strains with optimized Ester-producing capabilities.
Paloma Manzanares – One of the best experts on this subject based on the ideXlab platform.
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Rational selection of non-Saccharomyces wine yeasts for mixed starters based on Ester formation and enological traits.
Food Microbiology, 2008Co-Authors: Fernando Viana, Salvador Genovés, Salvador Vallés, Paloma ManzanaresAbstract:Thirty-eight yeast strains belonging to the genera Candida, Hanseniaspora, Pichia, Torulaspora and Zygosaccharomyces were screened for Ester formation on synthetic microbiological medium. The genera Hanseniaspora and Pichia stood out as the best Acetate Ester producers. Based on the Ester profile Hanseniaspora guilliermondii 11027 and 11102, Hanseniaspora osmophila 1471 and Pichia membranifaciens 10113 and 10550 were selected for further characterization of enological traits. When growing on must H. osmophila 1471, which displayed a glucophilic nature and was able to consume more than 90% of initial must sugars, produced levels of acetic acid, medium chain fatty acids and ethyl Acetate, within the ranges described for wine. On the other hand, it was found to be a strong producer of 2-phenylethyl Acetate. Our data suggest that H. osmophila 1471 is a good candidate for mixed starters, although the possible interactions with S. cerevisiae deserve further research.
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Acetate Ester formation in wine by mixed cultures in laboratory fermentations.
International Journal of Food Microbiology, 2003Co-Authors: Virginia Rojas, José Vicente Gil, Francisco Piñaga, Paloma ManzanaresAbstract:Two non-Saccharomyces wine yeast strains, Hanseniaspora guilliermondii 11104 and Pichia anomala 10590, selected as good producers of Acetate Esters when grown on synthetic microbiological medium, have been tested in wine fermentations as mixed cultures together with Saccharomyces cerevisiae. Wines produced using mixed cultures showed levels of acetaldehyde, acetic acid, glycerol and total higher alcohols within the ranges described for wine, whereas an increase in Acetate Ester concentrations was found. Ethyl Acetate was the main Ester produced, and isoamyl Acetate and 2-phenylethyl Acetate made up the next largest group of Ester compounds in the wines analysed. H. guilliermondii 11104 was found to be a strong producer of 2-phenylethyl Acetate in both pure and mixed cultures whereas S. cerevisiae was the best producer of ethyl Esters. Mixed cultures did not influence ethyl Ester levels at all.
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Studies on Acetate Ester production by non-Saccharomyces wine yeasts
International journal of food microbiology, 2001Co-Authors: Virginia Rojas, José Vicente Gil, Francisco Piñaga, Paloma ManzanaresAbstract:A double coupling bioreactor system was used to fast screen yeast strains for the production of Acetate Esters. Eleven yeast strains were used belonging to the genera Candida, Hanseniaspora, Metschnikowia, Pichia, Schizosaccharomyces and Zygosacharomyces, mainly isolated from grapes and wine, and two wine Saccharomyces cerevisiae strains. The Acetate Ester forming activities of yeast strains belonging to the genera Hanseniaspora (Hanseniaspora guilliermondii and H. uvarum) and Pichia (Pichia anomala) showed different substrate specificities and were able to produce ethyl Acetate, geranyl Acetate, isoamyl Acetate and 2-phenylethyl Acetate. The influence of aeration culture conditions on the formation of Acetate Esters by non-Saccharomyces wine yeast and S. cerevisiae was examined by growing the yeasts on synthetic microbiological medium. S. cerevisiae produced low levels of Acetate Esters when the cells were cultured under highly aeration conditions, while, under the same conditions, H. guilliermondii 11104 and P. anomala 10590 were found to be strong producers of 2-phenylethyl Acetate and isoamyl Acetate, respectively.