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1
Haidar, Ihab, Elie Desmond-Le Quéméner, Jean-Pierre Barbot, Jérôme Harmand e Alain Rapaport. "Modeling and Optimal Control of an Electro-Fermentation Process within a Batch Culture". Processes 10, n. 3 (8 marzo 2022): 535. http://dx.doi.org/10.3390/pr10030535.
Testo completoAbstract (sommario):
Electro-fermentation is a novel process that consists in coupling a microbial fermentative metabolism with an electrochemical system. In such a process, the electrodes act either as the electron sinks or sources modifying the fermentation balance of a microbial fermentative metabolism and provide new options for the control of microbial activity. A theoretical framework for the analysis and control of fermentations using electro-fermentation is currently lacking. In this paper, we propose a simple electro-fermentation model in which a population of fermentative bacteria switch between two metabolic behaviors in response to different electrode potentials. We then mathematically analyze optimal strategies to maximize the production of one of the rising products in a batch fermentation using Pontryagin’s Maximum Principle. The obtained results show that, in some experimental configurations, a dynamic control of the electrode potential is required for the maximization of the desired product. Consequences of the obtained optimal strategy for driving electro-fermentation experiments are discussed through a realistic example. This analysis also highlights that the transition rates between fermentation and electro-fermentation behaviors are currently unknown and would be crucial to quantify in order to apply such a control approach.
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Alberico, Grazia, Angela Capece, Gianluigi Mauriello, Rocchina Pietrafesa, Gabriella Siesto, Teresa Garde-Cerdán, Diamante Maresca, Raffaele Romano e Patrizia Romano. "Influence of Microencapsulation on Fermentative Behavior of Hanseniaspora osmophila in Wine Mixed Starter Fermentation". Fermentation 7, n. 3 (13 luglio 2021): 112. http://dx.doi.org/10.3390/fermentation7030112.
Testo completoAbstract (sommario):
In recent years, as a consequence of the re-evaluation of the role of non-Saccharomyces yeasts, several studies have been conducted on the use of controlled mixed fermentations with Saccharomyces and different non-Saccharomyces yeast species from the winemaking environment. To benefit from the metabolic particularities of some non-Saccharomyces yeasts, the management of a non-Saccharomyces strain in mixed fermentation is a crucial step, in particular the use of procedures addressed to increase the persistence of non-Saccharomyces strains during the fermentative process. The use of microencapsulation for cell immobilization might represent a strategy for enhancing the competitiveness of non-Saccharomyces yeasts during mixed fermentation. This study was aimed to assess the fermentative performance of a mixed starter culture, composed by a wild Hanseniaspora osmophila strain (ND1) and a commercial Saccharomyces cerevisiae strain (EC1118). For this purpose, free and microencapsulated cells of ND1 strain were tested in co-culture with EC1118 during mixed fermentations in order to evaluate the effect of the microencapsulation on fermentative behavior of mixed starter and final wine composition. The data have shown that H. osmophila cell formulation affects the persistence of both ND1 and EC1118 strains during fermentations and microencapsulation resulted in a suitable system to increase the fermentative efficiency of ND1 strain during mixed starter fermentation.
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Casalta, Erick, Carla Sabatier, Giovana Girardi-Piva, Gabriel Dournes, Aurélie Roland e Jean-Roch Mouret. "Impact of phytosterol addition on fermentation progress and volatile compounds synthesis during alcoholic fermentation in synthetic and natural grape musts". OENO One 57, n. 3 (19 luglio 2023): 41–52. http://dx.doi.org/10.20870/oeno-one.2023.57.3.7479.
Testo completoAbstract (sommario):
Lipid nutrition is an important factor for yeast during alcoholic fermentation. Although recent research reports have revisited the role of sterols during alcoholic fermentation, our knowledge of lipids assimilation and volatile compound biogenesis remains partial. This study aimed to find out more about the impact of grape must phytosterol content on fermentative kinetics, nitrogen assimilation by yeast and fermentative aroma synthesis. To that end, experimental fermentations were performed in synthetic and Chardonnay musts supplemented with different phytosterol concentrations (0, 1, 3 and 5 mg/L). Sterols addition significantly increased the maximum CO2 production rate while reducing fermentation duration. This can be explained by higher nitrogen assimilation by yeast due to sterols, which leads to higher yeast growth and better viability at the end of the fermentation process. Regarding the aromatic profile, sterol addition also significantly increased acetate esters, ethyl esters, fusel alcohols and medium-chain fatty acids production. These new advances highlight the major role of phytosterols in fermentation control and wine aroma profile.
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Agostini, J. S., R. P. Biasi, K. K. Tanssini e M. F. Bocca. "Physical, chemical and microbiological characterization of cupuassu seed during fermentation". Scientific Electronic Archives 14, n. 3 (26 febbraio 2021): 36–45. http://dx.doi.org/10.36560/14320211325.
Testo completoAbstract (sommario):
The cupuassu’s seeds are similar to cocoa, being possible to apply fermentative techniques used to obtain nibs and cupulate. The aim of this work to study the physicochemical transformations during the cupuassu´s seeds fermentation. For this purpose, frozen seeds from a pulp processing industry were fermented in three batches of 20 kg for seven days at room temperature. During the fermentation process, seed mass temperature, dimensions, density and composition of the kernels, color indexes (L*, C* and H*), microbiological analyzis (mesophiles, molds and yeasts), cut-proof, physicochemical analyzis (pH, acidity and glucose reducing sugars and non sucrose reduction) and centesimal composition (ashes, lipids, proteins and carbohydrates) were analyzed from triplicates. The results were expressed as dry basis. During the fermentations, the great temperatures were reached. The maximus were 43,44 and 47 ºC in three fermentations. It was observed during the fermentation process: seed darkening (L*) and color intensity reduction (Chroma), pH increase, sugar reduction and acidity reduction. The ash, lipid and protein contents were not significantly influenced by the fermentation time. According to the cut test, the kernels of 3rd fermentation, whose maximum temperature was higher, were classified as type 2 and the others as type 3. The values of apparent density, dimensions, mass and composition of seeds demonstrated that during the fermentation there was a decrease in volume with a higher proportion of cotyledon compared to testa. There was an increase in counts of total mesophiles aerobic microorganisms, molds and yeasts, during the fermentative process.
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del Fresno, Juan Manuel, Francisco Carrau, Carlos Escott, Cristian Vaquero, Carmen González e Antonio Morata. "Use of Hanseniaspora spp. in sequential fermentation with Saccharomyces cerevisiae to improve the aromatic complexity of Albillo Mayor white wines". BIO Web of Conferences 68 (2023): 02029. http://dx.doi.org/10.1051/bioconf/20236802029.
Testo completoAbstract (sommario):
Hanseniaspora spp apiculate yeasts can be found on ripe grape skins and during the first six days of the alcoholic fermentation. Generally, these yeasts have poor characteristics for its industrial application in winery as they are related with low fermentative power, low resistance to SO2 and even high volatile acidity production. However, some species have a better fermentative capacity and are producers of certain floral and fruity volatiles. This is the case of the two strains used in this study. Hanseniaspora vineae (HV) has a fermentative power around 8-10% v/v, low volatile acidity production and produces high levels of 2-phenylethyl acetate. Similarly, Hanseniaspora opuntiae (HO) also produces a low volatile acidity providing sweet and floral aromas, but has a fermentative power around 6% v/v, which means that it must be used in sequential fermentation with Saccharomyces cerevisiae (SC). In addition, several studies indicate that both species can increase the mouthfeel and wine body. The aim of this study was to evaluate the use of HV and HO in sequential fermentation with SC to improve the sensory profile of high quality white wines from the neutral grape variety Albillo Mayor. Fermentations were performed in triplicate in 150 L stainless steel barrels with grapes from the 2021 vintage. Pure SC fermentations were used as controls. After the fermentation, the polysaccharide content and the colour was measured, and an intensive study of the aromatic profile was done.
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Zhang, Da Wei, Wenbin Dong, Lei Jin, Jie Zhang e Yuan Chang Jin. "Isolation of Saccharomyces cerevisiae YDJ05 from the Spontaneous Fermentation Pear Wine and Study of the Yeast Growth Dynamics during the Association Fermentation". Advanced Materials Research 156-157 (ottobre 2010): 266–71. http://dx.doi.org/10.4028/www.scientific.net/amr.156-157.266.
Testo completoAbstract (sommario):
Five preponderant yeast strains (YDJ01, YDJ02, YDJ03, YDJ04 and YDJ05) were isolated from the spontaneous fermentation pear wine as source of yeast for wine making from pear. Ethanol yield of YDJ05 was the highest and its using rapidity of the sugar was the most quickly. YDJ05 was identified as Saccharomyces cerevisiae and named Saccharomyces cerevisiae YDJ05. In addition, the fermentation dynamics of three yeast strains (Saccharomyces cerevisiae YDJ05, “Angle” yeast and Saccharomyces cerevisiae GIM2.39) were studied including single fermentation and associated fermentation. The fermentative behavior of three strains changed in association fermentations (Saccharomyces cerevisiae YDJ05 and “Angle” yeast, Saccharomyces cerevisiae YDJ05 and Saccharomyces cerevisiae GIM2.39). Results indicated that the qualities of pear wines made from association fermentations were better than that of single fermentations. The pear wine fermented associated by Saccharomyces cerevisiae YDJ05 and Saccharomyces cerevisiae GIM2.39 was the best in quality by sensory evaluation among all pear wines whose ethanol concentration was 10.3% (v/v). Saccharomyces cerevisiae YDJ05 and mai could be excellent potential source of strains.
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Sica, Jacopo, Chiara Vendramini, Chiara Nadai, Zeno Molinelli, Milena Carlot, Alessio Giacomini e Viviana Corich. "Strain prevalence and killer factor only partially influence the fermentation activity of pairwise Saccharomyces cerevisiae wine strains inoculation". PLOS ONE 19, n. 4 (29 aprile 2024): e0300212. http://dx.doi.org/10.1371/journal.pone.0300212.
Testo completoAbstract (sommario):
Commercial Saccharomyces cerevisiae starters are single-strain cultures widely used in winemaking to optimise the fermentation process and improve the organoleptic quality of wine. Unfortunately, the worldwide extensive use of a limited number of industrial strains led to the standardisation of the sensory properties, reducing the identity of wines. Therefore, the use of multi-strain S. cerevisiae starters can be an alternative tool to alter the sensory profile of wines, increasing the diversity of wine styles. However, this strategy may be interesting only if the overall fermentation kinetics is not affected. To date, there is a lack of information regarding the influence of multi-strain starters on the overall fermentation process in wine. In this context, killer toxins, affecting the viability of sensitive strains, can play a significant role. This study aimed to evaluate the effects of pairing eight wine strains of S. cerevisiae (two sensitive, three neutral and three killer) in co-fermentations compared to single-strain fermentations. Results evidenced that, among co-fermentations where the strain prevalence was significant, the killer strains constituted 79% to 100% of the total yeast population when co-inoculated with a sensitive one. However, in most of the cases, co-fermentations kinetics were similar to those of sensitive strains or worse than both strains. Thus, the presence of a killer strain alone is not sufficient to predict the overall fermentation progress, which is an essential information in winemaking. Interestingly, the neutral strain P304.4 was always prevalent, regardless of the second strain and, in most of the co-fermentations, the overall fermentation trend was similar to the P304.4 single-strain fermentation. Regardless of killer activity, our results suggest that the effect of strains on fermentative kinetics is still unpredictable, and further studies are needed to thoroughly explore strain to strain interactions in winemaking.
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Schmechel, Carmen. "Descartes on fermentation in digestion: iatromechanism, analogy and teleology". British Journal for the History of Science 55, n. 1 (11 gennaio 2022): 101–16. http://dx.doi.org/10.1017/s0007087421000819.
Testo completoAbstract (sommario):
AbstractFermentation is a cornerstone phenomenon in Cartesian physiology, accounting for processes such as digestion or blood formation. I argue that the previously unrecognized conceptual tension between the terms ‘fermentation’ and ‘concoction’ reflects Descartes's efforts towards a novel, more thoroughly mechanistic theory of physiology, set up against both Galenism and chymistry. Similarities with chymistry as regards fermentation turn out either epistemologically superficial, or based on shared earlier sources. Descartes tentatively employs ‘fermentation’ as a less teleological alternative to ‘concoction’, later renouncing the explicit use of the term, possibly to avoid chymical overtones. However, his continued use of analogies with fermentative processes in the natural world and in winemaking, coupled with a strong ontological commitment (the stance that the physiological processes are actual fermentations), leads to a reintroduction of natural teleology in his medical system, which I argue may be understood in an Aristotelian sense of ‘simple necessity’. The paper reveals a more nuanced account of Cartesian fermentative medicine, delineating some of its tensions with regard to chymistry as they play out in the dynamics of fermentation and concoction, and linking the analogies to fermentation processes to the difficulties in erasing teleology altogether.
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Zannini, Emanuele, Kieran M. Lynch, Laura Nyhan, Aylin W. Sahin, Patrick O’ Riordan, Daenen Luk e Elke K. Arendt. "Influence of Substrate on the Fermentation Characteristics and Culture-Dependent Microbial Composition of Water Kefir". Fermentation 9, n. 1 (29 dicembre 2022): 28. http://dx.doi.org/10.3390/fermentation9010028.
Testo completoAbstract (sommario):
Water kefir is a sparkling fermented beverage produced by fermenting water kefir grains in a sucrose solution containing dried fruits or fruit extracts. The objective of this study was to investigate the influence of substrate composition on the fermentation kinetics and culture-dependent microbial composition of water kefir. First, the impact of different fruit substrates and nitrogen limitation was examined. Fermentation of different fruit-based media with a single water kefir culture demonstrated that the substrate mainly influenced the type and ratio of the organic acids produced. These organic acid profiles could be linked to the culture-dependent microbial composition. In addition, the microbial composition and the associated dominant microorganisms observed were influenced by the water kefir fermentation conditions. Investigation of the effect of nitrogen limitation on the fermentation kinetics of several water kefir cultures showed that under such conditions, the fermentative capacity of the cultures declined. However, this decline was not immediate, and specific water kefir microorganisms may have enabled some cultures to maintain a higher fermentative capacity for longer. Thus, the water kefir fermentation kinetics and characteristics could be linked to the substrate composition, microorganisms present, and the process conditions under which the fermentations were performed.
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Yaacob, Norhayati, Mohd Shukuri Mohamad Ali, Abu Bakar Salleh e Nor Aini Abdul Rahman. "Effects of glucose, ethanol and acetic acid on regulation of ADH2 gene fromLachancea fermentati". PeerJ 4 (10 marzo 2016): e1751. http://dx.doi.org/10.7717/peerj.1751.
Testo completoAbstract (sommario):
Background.Not all yeast alcohol dehydrogenase 2 (ADH2) are repressed by glucose, as reported inSaccharomyces cerevisiae.Pichia stipitisADH2 is regulated by oxygen instead of glucose, whereasKluyveromyces marxianusADH2 is regulated by neither glucose nor ethanol. For this reason, ADH2 regulation of yeasts may be species dependent, leading to a different type of expression and fermentation efficiency.Lachancea fermentatiis a highly efficient ethanol producer, fast-growing cells and adapted to fermentation-related stresses such as ethanol and organic acid, but the metabolic information regarding the regulation of glucose and ethanol production is still lacking.Methods.Our investigation started with the stimulation of ADH2 activity fromS. cerevisiaeandL. fermentatiby glucose and ethanol induction in a glucose-repressed medium. The study also embarked on the retrospective analysis of ADH2 genomic and protein level through direct sequencing and sites identification. Based on the sequence generated, we demonstrated ADH2 gene expression highlighting the conserved NAD(P)-binding domain in the context of glucose fermentation and ethanol production.Results.An increase of ADH2 activity was observed in starvedL. fermentati(LfeADH2) andS. cerevisiae(SceADH2) in response to 2% (w/v) glucose induction. These suggest that in the presence of glucose, ADH2 activity was activated instead of being repressed. An induction of 0.5% (v/v) ethanol also increased LfeADH2 activity, promoting ethanol resistance, whereas accumulating acetic acid at a later stage of fermentation stimulated ADH2 activity and enhanced glucose consumption rates. The lack in upper stream activating sequence (UAS) and TATA elements hindered the possibility of Adr1 binding to LfeADH2. Transcription factors such as SP1 and RAP1 observed in LfeADH2 sequence have been implicated in the regulation of many genes including ADH2. In glucose fermentation,L. fermentatiexhibited a bell-shaped ADH2 expression, showing the highest expression when glucose was depleted and ethanol-acetic acid was increased. Meanwhile, S. cerevisiaeshowed a constitutive ADH2 expression throughout the fermentation process.Discussion.ADH2 expression inL. fermentatimay be subjected to changes in the presence of non-fermentative carbon source. The nucleotide sequence showed that ADH2 transcription could be influenced by other transcription genes of glycolysis oriented due to the lack of specific activation sites for Adr1. Our study suggests that if Adr1 is not capable of promoting LfeADH2 activation, the transcription can be controlled by Rap1 and Sp1 due to their inherent roles. Therefore in future, it is interesting to observe ADH2 gene being highly regulated by these potential transcription factors and functioned as a promoter for yeast under high volume of ethanol and organic acids.
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Hallenbeck, P. C. "Fundamentals of the fermentative production of hydrogen". Water Science and Technology 52, n. 1-2 (1 luglio 2005): 21–29. http://dx.doi.org/10.2166/wst.2005.0494.
Testo completoAbstract (sommario):
The molecular details behind hydrogen evolution during fermentation are reviewed. Hydrogen is evolved by hydrogenase, a class of enzymes containing complex metallo-centers. In most cases, sugars are degraded to pyruvate which in turn is converted to a variety of fermentation products. Various pathways leading to fermentative hydrogen generation are outlined and discussed. Thermophilic fermentations have higher yields than mesophilic ones. Yields are thought to be limited to 4H2 per glucose under standard conditions. The highlights of some actual studies of fermentations are presented and ways of potentially increasing hydrogen yields are discussed. It may be possible to achieve higher hydrogen yields by carrying out fermentations under microaerobic conditions where limited respiration could provide additional reducing power to drive the nearly complete conversion of sugar substrates to hydrogen.
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Malićanin, Marko, Bojana Danilović, Sandra Stamenković Stojanović, Dragan Cvetković, Miodrag Lazić, Ivana Karabegović e Dragiša Savić. "Pre-Fermentative Cold Maceration and Native Non-Saccharomyces Yeasts as a Tool to Enhance Aroma and Sensory Attributes of Chardonnay Wine". Horticulturae 8, n. 3 (28 febbraio 2022): 212. http://dx.doi.org/10.3390/horticulturae8030212.
Testo completoAbstract (sommario):
The oenological potential of native strains of Metschnikowia pulcherrima B-5 and Candida famata WB-1, isolated from blackberries, was investigated in pure and sequential fermentation of Chardonnay grape with commercial Saccharomyces cerevisiae QA23. The effect of pre-fermentative cold maceration was also analysed. The fermentations were performed in the pilot-scale trials and the profile of volatile compounds and their sensory characteristics were determined. The application of C. famata WB-1 and M. pulcherrima B-5 reduced the volatile acidity and increased total polyphenols of the wines, compared to the control samples. Higher alcohols and esters were dominant, while fatty acids and aldehydes and ketones were also detected. Esters had the greatest contribution to sensory characteristics, especially the development of floral and fruity aromas. Most esters were present in lower concentrations in sequential fermentations compared to the pure fermentations with M. pulcherrima B-5 or C. famata WB-1. Pre-fermentative maceration positively affected both the aroma and the sensory profile. The best sensory score was determined for wines produced using C. famata WB-1 in the fermentations without pre-fermentative maceration, and the sequential fermentation of M. pulcherrima B-5 with maceration. Native strains of M. pulcherrima B-5 and C. famata WB-1 have shown great potential for the enhancement of the aromatic and sensory profile of Chardonnay wine.
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Figueira, Ricardo, Lucas Felipe Dos Ouros, Isabela Penteriche De Oliveira, Thalia Lee Lopes De Andrade e Waldemar Gastoni Venturini Filho. "QUANTIFICAÇÃO DO METABOLISMO RESPIROFERMENTATIVO DE LEVEDURAS DE CERVEJA, VINHO E PÃO POR MÉTODO ESTEQUIOMÉTRICO". ENERGIA NA AGRICULTURA 36, n. 1 (20 luglio 2021): 10–16. http://dx.doi.org/10.17224/energagric.2021v36n1p10-16.
Testo completoAbstract (sommario):
QUANTIFICAÇÃO DO METABOLISMO RESPIROFERMENTATIVO DE LEVEDURAS DE CERVEJA, VINHO E PÃO POR MÉTODO ESTEQUIOMÉTRICO RICARDO FIGUEIRA1, LUCAS FELIPE DOS OUROS1, ISABELA PENTERICHE DE OLIVEIRA1, THALIA LEE LOPES DE ANDRADE1, WALDEMAR GASTONI VENTURINI FILHO1 1Departamento de Produção Vegetal/Área Horticultura, Faculdade de Ciências Agronômicas, UNESP. Av. Universitária, 3780 - Altos do Paraíso, CEP 18610-034, Botucatu, SP, Brasil. ricardo.figueira@unesp.br; lucasouros@hotmail.com; isapenteriche@hotmail.com; thalialda@hotmail.com; waldemar.venturini@unesp.br RESUMO: A levedura alcoólica apresenta metabolismo respirofermentativo, respirando e fermentando simultaneamente. É possível mensurar o metabolismo fermentativo e respiratório de uma levedura alcoólica, conhecendo a quantidade de etanol formado na fermentação e de gás carbônico proveniente dos processos de respiração e fermentação. O objetivo deste trabalho foi calcular a taxa respiratória e fermentativa de diferentes cepas de levedura alcoólica por meio de método estequiométrico. Foram utilizadas cinco diferentes cepas de leveduras (panificação, cervejeira de alta fermentação (ale), cervejeira de baixa fermentação (lager), vinho tinto e vinho branco). O meio de cultivo foi mosto de cana de açúcar (15 °Brix). A fermentação transcorreu durante 8 horas, na temperatura ambiente, em fermentador aberto. A levedura cervejeira de alta fermentação e de panificação apresentaram as maiores taxas respiratórias (19,17% e 19,12%), as leveduras de vinho branco e cervejeira de baixa fermentação tiveram as maiores taxas fermentativas (90,48% e 89,67%), a levedura cervejeira de baixa fermentação produziu a maior quantidade de etanol (7,57%) e a levedura de panificação apresentou maior capacidade metabólica (131,59 g de sacarose consumidos). Palavras-chave: fermentação, respiração, Saccharomyces cerevisiae. QUANTIFICATION OF RESPIRO-FERMENTATIVE METABOLISM OF BEER, WINE AND BREAD YIELD BY ESTEQUIOMETRIC METHOD ABSTRACT: The alcoholic yeast can breathe and ferment simultaneously, called respiro-fermentative metabolism. Yeast’s respiration and fermentation metabolism can be measured considering the amount of ethanol produced in the fermentation process and the carbon dioxide produced in both respiration and fermentation processes. This research focused on calculating the respiration and fermentation rates of five alcoholic yeast strains (baker’s, beer top-fermenting (ale), beer bottom fermenting (lager), red wine and white wine) from the stoichiometry. Sugar cane must (15 °Brix) was used as growth medium. Fermentation was performed in an open vessel at room temperature. A sample was taken hourly, and the fermentation process ended after 8 h. Beer top-fermenting yeast and baker’s yeast resulted in higher respiration rates (19.17% and 19.12%), while white wine yeast and bottom-fermenting yeast resulted in higher fermentation rates (90.48% and 89.67%). Bottom-fermenting yeast produced higher amount of ethanol (7.57%) and baker’s yeast presented higher metabolic activity (131.59 g of sucrose consumed). Keywords: fermentation, respiration, Saccharomyces cerevisiae.
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Feghali, Nadine, Angela Bianco, Giacomo Zara, Edouard Tabet, Chantal Ghanem e Marilena Budroni. "Selection of Saccharomyces cerevisiae Starter Strain for Merwah Wine". Fermentation 6, n. 2 (22 aprile 2020): 43. http://dx.doi.org/10.3390/fermentation6020043.
Testo completoAbstract (sommario):
In order to select Saccharomyces cerevisiae starter strains for ‘‘Merwah’’ wine production, three strains (M.6.16, M.10.16, and M.4.17) previously isolated from ‘‘Merwah’’ must and characterized at the lab scale were tested in pilot-scale fermentation in a Lebanese winery during the 2019 vintage. The three inoculated musts were compared to that obtained with a spontaneous fermentation. During the fermentations, must samples were taken to evaluate the dominance of the inoculated strains, and at the end of fermentation, the obtained wines were subjected to chemical and sensorial characterization. Molecular monitoring by interdelta analysis revealed that only M.4.17 was able to complete the fermentation and dominate over the wild yeasts. Based on the analysis of principal technological parameters (i.e., residual sugar, fermentative vigor, sulfur production, and acetic acid) and sensorial analysis of the wines obtained, M.4.17 was selected as an adequate starter for the production of typical ‘‘Merwah’’ wine.
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van Wyk, Niël, Florian Michling, Dennis Bergamo, Sylvia Brezina, Isak S. Pretorius, Christian von Wallbrunn e Jürgen Wendland. "Effect of Isomixing on Grape Must Fermentations of ATF1–Overexpressing Wine Yeast Strains". Foods 9, n. 6 (2 giugno 2020): 717. http://dx.doi.org/10.3390/foods9060717.
Testo completoAbstract (sommario):
Speeding up grape must fermentation would be of great economic benefit. We subjected Saccharomyces cerevisiae VIN13 and two recombinant VIN13-strains expressing ATF1 alleles under two different promoters (either PGK1 or HXT7) to four styles of grape must fermentations; we then assessed the effect of constantly stirring a must fermentation (isomixing). The four different fermentation setups were as follows: isomixed, closed in an ANKOM Rf Gas productions system; isomixed, open in a stirred tall tube cylinder; static, closed constituting a conventional fermentation in a wine bottle equipped with an airlock and static; and static, open in a tall tube cylinder (without stirring). We report on major fermentation parameters and the volatile aroma compositions generated in the finished wines. The primary fermentations of the strains subjected to constant stirring finished after 7 days, whereas the static fermentations reached dryness after 19 days. The wines derived from isomixed fermentations produced approximately 0.7% less ethanol compared to the unstirred fermentations. The speed that the isomixed fermentation took to reach completion may provide an alternative to static fermentations in the preparation of base wines for sparkling wine production. The observed increase of volatiles of isomixed fermentations merits further investigation.
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Vaquero, Cristian, Iris Loira, María Antonia Bañuelos, José María Heras, Rafael Cuerda e Antonio Morata. "Industrial Performance of Several Lachancea thermotolerans Strains for pH Control in White Wines from Warm Areas". Microorganisms 8, n. 6 (1 giugno 2020): 830. http://dx.doi.org/10.3390/microorganisms8060830.
Testo completoAbstract (sommario):
In the current scenario of climatic warming, the over-ripening of grapes increases the sugar content, producing flat and alcoholic wines with low acidity, high pH and low freshness. Additionally, a high pH makes wines more chemically and microbiologically unstable, requiring a higher sulphite content for preservation. Some strains of Lachancea thermotolerans can naturally lower the pH of wine by producing lactic acid from sugars; this pH reduction can reach 0.5 units. The industrial performance of four selected strains has been compared with that of two commercial strains and with that of Saccharomyces cerevisiae. The yeasts were assessed under variable oenological conditions, measuring lactic acid production and fermentative performance at two fermentation temperatures (17 and 27 °C), and in the presence or absence of sulphites (25 and 75 mg/L). Lactic acid production depends on yeast populations, with higher concentrations being reached when the microbial population is close to or above 7-log CFU/mL. A temperature effect on acidification can also be observed, being more intense at higher fermentation temperatures for most strains. Ethanol yield ranged from 7–11% vol., depending on the fermentation conditions (temperature and SO2) at day 12 of fermentation, compared with 12% for the S. cerevisiae control in micro-fermentations. The production of fermentative esters was higher at 27 °C compared with 17 °C, which favoured the production of higher alcohols. Volatile acidity was moderate under all fermentation conditions with values below 0.4 g/L.
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Roca-Mesa, Helena, Sonia Sendra, Albert Mas, Gemma Beltran e María-Jesús Torija. "Nitrogen Preferences during Alcoholic Fermentation of Different Non-Saccharomyces Yeasts of Oenological Interest". Microorganisms 8, n. 2 (22 gennaio 2020): 157. http://dx.doi.org/10.3390/microorganisms8020157.
Testo completoAbstract (sommario):
Non-Saccharomyces yeasts have long been considered spoilage microorganisms. Currently, oenological interest in those species is increasing, mostly due to their positive contribution to wine quality. In this work, the fermentative capacity and nitrogen consumption of several non-Saccharomyces wine yeast (Torulaspora delbrueckii, Lachancea thermotolerans, Starmerella bacillaris, Hanseniaspora uvarum, and Metschnikowia pulcherrima) were analyzed. For this purpose, synthetic must with three different nitrogen compositions was used: a mixture of amino acids and ammonium, only organic or inorganic nitrogen. The fermentation kinetics, nitrogen consumption, and yeast growth were measured over time. Our results showed that the good fermentative strains, T. delbrueckii and L. thermotolerans, had high similarities with Saccharomyces cerevisiae in terms of growth, fermentation profile, and nitrogen assimilation preferences, although L. thermotolerans presented an impaired behavior when only amino acids or ammonia were used, being strain-specific. M. pulcherrima was the non-Saccharomyces strain least affected by the nitrogen composition of the medium. The other two poor fermentative strains, H. uvarum and S. bacillaris, behaved similarly regarding amino acid uptake, which occurred earlier than that of the good fermentative species in the absence of ammonia. The results obtained in single non-Saccharomyces fermentations highlighted the importance of controlling nitrogen requirements of the wine yeasts, mainly in sequential fermentations, in order to manage a proper nitrogen supplementation, when needed.
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Hu, Lanlan, Rui Liu, Xiaohong Wang e Xiuyan Zhang. "The Sensory Quality Improvement of Citrus Wine through Co-Fermentations with Selected Non-Saccharomyces Yeast Strains and Saccharomyces cerevisiae". Microorganisms 8, n. 3 (26 febbraio 2020): 323. http://dx.doi.org/10.3390/microorganisms8030323.
Testo completoAbstract (sommario):
Co-fermentation of selected non-Saccharomyces yeast strain with Saccharomyces cerevisiae is regarded as a promising approach to improve the sensory quality of fruit wine. To evaluate the effects of co-fermentations between the selected non-Saccharomyces yeast strains (Hanseniaspora opuntiae, Hanseniaspora uvarum and Torulaspora delbrueckii) and S. cerevisiae on the sensory quality of citrus wine, the fermentation processes, the chemical compositions, and the sensory evaluations of citrus wines were analyzed. Compared with those of S. cerevisiae fermentation, co-fermentations produced high sensory qualities, and S. cerevisiae/H. opuntiae co-fermentation had the best sensory quality followed by Sc-Hu and Sc-Td co-fermentations. Additionally, all the co-fermentations had a lower amount of ethanol and total acidity, higher pH value, and higher content of volatile aroma compounds, especially the content of higher alcohol and ester compounds, than those of S. cerevisiae fermentation. Therefore, co-fermentations of the non-Saccharomyces yeast strains and S. cerevisiae could be employed to improve the sensory quality of citrus wines. These results would provide not only methods to improve the sensory quality of citrus wine, but also a valuable reference for the selection of non-Saccharomyces yeast strains for fruit wine fermentation.
19
Ribeiro, Carlos Alberto França, e Jorge Horii. "Negative H2S character and flocculation as yeast strain markers for inoculum recovery". Scientia Agricola 61, n. 3 (giugno 2004): 292–97. http://dx.doi.org/10.1590/s0103-90162004000300009.
Testo completoAbstract (sommario):
Routine identification of yeast behavior is essential to measure the control of the alcohol production process and to maintain product quality standards. This work utilized the non-hydrogen sulfide production and flocculation traits as characteristic strain markers for the evaluation of cell recycling during the alcoholic fermentation process for production of sugarcane alcohol. This study evaluated the behavior of a recombinant yeast bank made by protoplast fusion, for strain screening purposes; strain fermentative kinetics in comparison to commercial baker yeast; viability and recovery of the selected strain on differential media, after five consecutive fermentation batches; and the recovery of the selected strain from fermentation with mixed strain cultures. The strain selected for the H2S negative character kept its viability during successive recyclings, with contamination levels not detected by the method of analysis. It also presented a kinetic behavior similar to that of baker yeast, either in single or mixed culture fermentations, opening new possibilities for further work on quality control of cell recycling in the alcoholic fermentation process.
20
Guerrini, Simona, Viola Galli, Silvia Mangani e Lisa Granchi. "Influence of Cryoextraction and Cold Pre-Fermentative Maceration on the Yeast Microbiota and the Volatile Compounds Profile of Sangiovese Wine". Fermentation 10, n. 3 (6 marzo 2024): 148. http://dx.doi.org/10.3390/fermentation10030148.
Testo completoAbstract (sommario):
Low-temperature treatments can be applied to grapes or must before alcoholic fermentation to enhance the wine’s sensory characteristics. Several studies have shown that such practices have a positive effect on the polyphenol profile of the wine, but only a few surveys have examined the effect of these treatments on the yeast microbiota of grapes and wine. Therefore, this study aimed to evaluate how cryoextraction (freezing the grape with liquid nitrogen) and cold pre-fermentative maceration (at 5 °C for 48 h) affect the Saccharomyces and non-Saccharomyces populations during the winemaking process of red grapes, cv Sangiovese, conducted at two temperatures (20 and 30 °C). This research analyzed the concentration of various yeast species, their fermentation abilities, and the resulting wine’s aromatic profile. The Principal Component Analysis performed on yeast concentrations during the fermentations of various wines did not group the experimental wines based on treatment. However, the same groupings were highlighted when the concentrations of the volatile compounds, quantified in the experimental wines, were processed using the same statistical approach. Therefore, cryoextraction and cold pre-fermentative maceration seem to contribute less to the aromatic profile than the yeasts involved in the fermentation process.
21
Ellacuriaga, Marcos, María Victoria Gil e Xiomar Gómez. "Syngas Fermentation: Cleaning of Syngas as a Critical Stage in Fermentation Performance". Fermentation 9, n. 10 (9 ottobre 2023): 898. http://dx.doi.org/10.3390/fermentation9100898.
Testo completoAbstract (sommario):
The fermentation of syngas is an attractive technology that can be integrated with gasification of lignocellulosic biomass. The coupling of these two technologies allows for treating a great variety of raw materials. Lignin usually hinders microbial fermentations; thus, the thermal decomposition of the whole material into small molecules allows for the production of fuels and other types of molecules using syngas as substrate, a process performed at mild conditions. Syngas contains mainly hydrogen, carbon monoxide, and carbon dioxide in varying proportions. These gases have a low volumetric energy density, resulting in a more interesting conversion into higher energy density molecules. Syngas can be transformed by microorganisms, thus avoiding the use of expensive catalysts, which may be subject to poisoning. However, the fermentation is not free of suffering from inhibitory problems. The presence of trace components in syngas may cause a decrease in fermentation yields or cause a complete cessation of bacteria growth. The presence of tar and hydrogen cyanide are just examples of this fermentation’s challenges. Syngas cleaning impairs significant restrictions in technology deployment. The technology may seem promising, but it is still far from large-scale application due to several aspects that still need to find a practical solution.
22
Pejin, Jelena, Olgica Grujic, Sinisa Markov, Suncica-Tanackov Kocic, Dragoljub Cvetkovic e Ilija Tanackov. "Fermentation temperature and wort composition influence on diacetyl and 2, 3-pentanedione contents in beer". Zbornik Matice srpske za prirodne nauke, n. 108 (2005): 229–38. http://dx.doi.org/10.2298/zmspn0508229p.
Testo completoAbstract (sommario):
Diacetyl and 2,3-pentanedione are important constituents of beer sensory properties. A new GC/MS method for diacetyl and 2,3-pentanedione content determination was developed. This method was applied for the determination of diacetyl and 2,3-pentanedione contents during beer fermentation (primary fermentation and maturation). Primary fermentations were carried out at different temperatures (8?C and 14?C). Primary fermentation temperature had a great influence on diacetyl and 2,3-pentanedione formation and reduction. Formation and reduction rates increased with the primary fermentation temperature increasment. Diacetyl and 2,3-pentanedione contents also increased with the corn grits increasment. Fermentations were carried out with Saccharomyces cerevisiae pure culture, specially prepared for each fermentation. This GC/MS method for diacetyl and 2,3-pentanedione determination was valuable for analysing the influence of wort composition or fermentation conditions such as primary fermentation temperature on their formation and reduction.
23
Miller, Konrad V., Even Arefaine, Ardic Arikal, Annegret Cantu, Raul Cauduro Girardello, Anita Oberholster, Hildegarde Heymann e David E. Block. "Development and Analysis of an Intensified Batch-Fed Wine Fermentation Process". Fermentation 8, n. 6 (7 giugno 2022): 268. http://dx.doi.org/10.3390/fermentation8060268.
Testo completoAbstract (sommario):
White wine fermentations are typically performed in an entirely batchwise manner, with yeast nutrients only added at the beginning of fermentation. This leads to slow (2+ weeks) fermentation cycle times, with large capital expenditures required to increase winery processing capacity. Prior attempts to speed fermentations via increasing temperature have resulted in unpalatable wine, and continuous fermentation processing is uneconomical and impractical in the winery setting. In this work, we measured yeast nutrient consumption as a function of fermentation progression at the 300 mL scale, and from this derived an equation to optimize yeast nutrient concentration as a function of fermentation progression. These findings were applied at the pilot scale in 150 L fermentors, which resulted in a 60% cycle time reduction versus “best practices” control fermentations. The resultant wines were compared via GC-MS as well as by a trained sensory panel. Organoleptic analysis found statistically significant, but overall, small differences in sensory characteristics between the control and process intensified wines. This intensified fermentation process shows great promise for fermented beverage producers wishing to maximize equipment utilization and debottleneck wineries or other beverage fermentation facilities.
24
Estela-Escalante, Waldir D., Jimy J. Perez-Escalante, Eduardo L. Fuentes-Navarro e Ricardo M. Pinillos-Miñano. "The Potential of Using Grapefruit Peel as a Natural Support for Yeast Immobilization During Beer Fermentation". Chemical & biochemical engineering quarterly 34, n. 2 (2020): 105–14. http://dx.doi.org/10.15255/cabeq.2020.1808.
Testo completoAbstract (sommario):
The potential use of grapefruit peel as support material for yeast immobilization during beer fermentation was evaluated. After conditioning, FTIR analysis revealed a higher quantity of methoxy (–OCH3) groups, suggesting that lignin is the major component of the support. Cell adhesion onto the conditioned support in 12°Plato laboratory malt wort was evaluated, observing a maximal cell adhesion (2.25 · 109 cells/gram of dried support) at 20 h of cultivation, remaining almost constant in the subsequent time points. Evaluations of the fermentative behaviour of the biocatalyst at 15±0.5 °C in a 14°Plato laboratory malt wort indicated good stability in terms of physical integrity (confirmed by SEM observation). The fermentation time was shortened to four days, and the rates of reducing sugar consumption and ethanol production were improved when compared to fermentations carried out with free suspended cells. These results show a promising potential of grapefruit peel as support material in beer fermentation.
25
Ambarsari, Indrie, Qanytah, Sigit Budi Santoso, Gama Noor Oktaningrum e Munir Eti Wulanjari. "Comparison of spontaneous and ragi fermentations on the physicochemical and functional properties of cereal flours". International Food Research Journal 29, n. 4 (19 agosto 2022): 909–17. http://dx.doi.org/10.47836/ifrj.29.4.18.
Testo completoAbstract (sommario):
Spontaneous and ragi fermentations are the most common methods in producing traditional fermented foods in Indonesia. The present work aimed to compare the impacts of spontaneous and ragi fermentations on cereal flour properties. Three kinds of cereal, namely whole sorghum, waxy coix, and white maize were processed into flours through spontaneous fermentation, ragi fermentation, and without fermentation (control). Fermentation methods were adopted from the Indonesian traditional processing methods. Cereal grains were immersed for 72 h in distilled water (1:2 w/v) for spontaneous fermentation, and in 1% ragi tapai solution (1:2 w/v) for ragi fermentation. Meanwhile, native flour (without fermentation) was produced by grounding and sieving the cereal grains. Results showed that both fermentation techniques significantly altered the physical properties of cereal flours, as indicated by the increase in lightness index and decrease in water-binding capacity and viscosity. However, cereal flours’ chemical and functional properties remain unchanged during fermentation, except for lipid and amylose. Spontaneous fermentation significantly resulted in the lowest lipid content of cereal flours, while ragi fermentation resulted in the lowest amylose content of cereal flours. Sorghum flour generally showed better nutritional properties among the examined cereal flours, especially lipid, protein, and dietary fibre. Meanwhile, waxy coix and white maize flours had the highest folate.
26
Ruiz-Rodríguez, Ana, Miguel Palma e Carmelo G. Barroso. "Influence of Temperature during Pre-Fermentative Maceration and Alcoholic Fermentation on the Phenolic Composition of ‘Cabernet Sauvignon’ Wines". Foods 10, n. 5 (11 maggio 2021): 1053. http://dx.doi.org/10.3390/foods10051053.
Testo completoAbstract (sommario):
This study presents the effects of different working temperatures on the transfer of compounds during the pre-fermentative and fermentative stages of the wine making process with ‘Cabernet Sauvignon’ grapes. Two different procedures have been evaluated. Firstly, the pre-fermentative maceration of the crushed grapes at two different temperatures (20 °C and 10 °C). Then, the alcoholic fermentation under two different sets of conditions, the fermentation at a constant temperature of 20 °C and the fermentation under a positive temperature gradient from 10 to 20 °C. According to the experimental results, the phenolic contents (total phenolics, total anthocyanins, and total tannins) were mainly conditioned by the fermentation temperature, however the pre-fermentative conditions also affected the content levels of these compounds. Furthermore, the use of a fermentation temperature gradient improved the organoleptic characteristics of the wines. However, the color was not as stable as that of wines produced through fermentation at a higher constant temperature. Consequently, the implementation of a temperature gradient during the alcoholic fermentation process is recommended and a longer period at high temperature over the last phase of the process would be desirable to obtain aromatic wines with the desirable color stability.
27
Hasalliu, Rozeta. "EVALUATION OF LACTIC ACID BACTERIA GROWTH DURING AUTOCHTHONOUS ALBANIAN KALLMET WINE PRODUCTION WITH SPONTANEOUS AND INOCULATED FERMENTATIONS". CBU International Conference Proceedings 5 (24 settembre 2017): 1199–203. http://dx.doi.org/10.12955/cbup.v5.1096.
Testo completoAbstract (sommario):
The grape used in wine making has many wild microorganisms like lactic acid bacteria, yeast, acetic acid bacteria. During the alcoholic fermentation, the evaluation of these microorganisms depends on their activity. There is an interaction between yeast and lactic acid bacteria during this period of wine making. In this study, we have made wine from the autochthonous Albanian grape Kallmet variety using the spontaneous fermentation and inoculated fermentation with the yeast Saccharomyces bayannus. Yeasts carry out the alcohol fermentation, and lactic acid bacteria make malolactic fermentation in wine. With this fermentation, lactic acid bacteria convert malic acid to lactic acid, reducing the acidity of the wine and create a microbiological stability. During the alcoholic fermentation, the evaluation of lactic acid bacteria is not required. The aim of our study is to evaluate the first quantity of lactic acid bacteria to Kallmet grape, their performance during the two fermentations, spontaneous and inoculated fermentations.
28
Cus, Franc, Neza Cadez e Peter Raspor. "Fungicide residues in grapes determined the dynamics of Saccharomyces cerevisiae strains during spontaneous wine fermentation". Zbornik Matice srpske za prirodne nauke, n. 121 (2011): 85–101. http://dx.doi.org/10.2298/zmspn1121085c.
Testo completoAbstract (sommario):
Impact of three fungicides against B. cinerea (iprodione, pyrimethanil and f ludioxonil plus cyprodinil) on the population of Saccharomyces cerevisiae strains during the spontaneous alcoholic fermentation was studied. With regard to the use of fungicides in the vineyard at two stages of the grapevine growth we followed four different spontaneous fermentations: control, iprodione, pyrimethanil and f ludioxonil plus cyprodinil. The fungicide residues in the grapes were determined by GC/MS system and the fermentations were followed by changes in yeast, sugar, and ethanol concentrations using colony counting and HPLC. The karyotype analysis of 473 isolates was done by pulsed-field gel electrophoresis. The fungicide residues in the grapes at the harvest were below the maximum residue limits. Isolates of S. cerevisiae were classified into 15 karyotype groups. The duration of the processes and the populations of the karyotypes differed between the fermentations. The iprodione and control fermentations lasted 36 days with the prevalence of karyotype A while the fludioxonil plus cyprodinil fermentation lasted 50 days and karyotype D led the process. In the pyrimethanil fermentation, none of the karyotypes prevailed in the must and the fermentation lasted much longer than others did (68 days). The results showed that the fungicide residues have an influence on the fermentation kinetics and selection of S. cerevisiae strains during the spontaneous alcoholic fermentation and therefore should be considered as an important factor that may indirectly influence the formation of fermentation aroma in the wine produced by such process.
29
Valera, María José, Valentina Olivera, Eduardo Boido, Eduardo Dellacassa e Francisco Carrau. "Wine Aroma Characterization of the Two Main Fermentation Yeast Species of the Apiculate Genus Hanseniaspora". Fermentation 7, n. 3 (21 agosto 2021): 162. http://dx.doi.org/10.3390/fermentation7030162.
Testo completoAbstract (sommario):
Hanseniaspora species are the main yeasts isolated from grapes and grape musts. Regarding genetic and phenotypical characterization, especially fermentative behavior, they can be classified in two technological clusters: the fruit group and the fermentation group. Among the species belonging to the last group, Hanseniaspora osmophila and Hanseniaspora vineae have been previously isolated in spontaneous fermentations of grape must. In this work, the oenological aptitudes of the two species of the fermentation group were compared with Saccharomyces cerevisiae and the main species of the fruit group, Hanseniaspora uvarum. Both H. osmophila and H. vineae conferred a positive aroma to final wines and no sensory defects were detected. Wines fermented with H. vineae presented significantly higher concentrations of 2-phenylethyl, tryptophol and tyrosol acetates, acetoin, mevalonolactone, and benzyl alcohol compared to H. osmophila. Sensorial analysis showed increased intensity of fruity and flowery notes in wines vinificated with H. vineae. In an evolutionary context, the detoxification of alcohols through a highly acetylation capacity might explain an adaption to fermentative environments. It was concluded that, although H. vineae show close alcohol fermentation adaptations to H. osmophila, the increased activation of phenylpropanoid metabolic pathway is a particular characteristic of H. vineae within this important apiculate genus.
30
Escott, Carlos, Carmen López, Iris Loira, Carmen González, María Antonia Bañuelos, Wendu Tesfaye, José Antonio Suárez-Lepe e Antonio Morata. "Improvement of Must Fermentation from Late Harvest cv. Tempranillo Grapes Treated with Pulsed Light". Foods 10, n. 6 (18 giugno 2021): 1416. http://dx.doi.org/10.3390/foods10061416.
Testo completoAbstract (sommario):
Pulsed light irradiation is a nonthermal technology currently used for the elimination of pathogens from a diverse range of food products. In the last two decades, the results obtained using PL at laboratory scale are encouraging wine experts to use it in the winemaking industry. PL can reduce native yeast counts significantly, which facilitates the use of starter cultures, reducing SO2 requirements at the same time. In this experimental set up, Tempranillo grapes were subjected to pulsed light treatment, and the fermentative performance of non-Saccharomyces yeasts belonging to the species Schizosaccharomyces pombe, Lachancea thermotolerans, Torulaspora delbrueckii, Metschnikowia pulcherrima and Hanseniaspora vineae was monitored in sequential fermentations against spontaneous fermentation and pure culture fermentation with the species Saccharomyces cerevisiae. The experimental analyses comprised the determination of anthocyanin (High performance liquid chromatography with photodiode array detector—HPLC-DAD), polyphenol index and colour (Ultraviolet-visible spectroscopy—UV-Vis spectrophotometer), fermentation-derived volatiles (Gas chromatography with flame ionization detector—GC-FID), oenological parameters (Fourier transform Infrared spectroscopy—FT-IR) and structural damage of the skin (atomic force microscopy—AFM). The results showed a decrease of 1.2 log CFU/mL yeast counts after pulsed light treatment and more rapid and controlled fermentation kinetics in musts from treated grapes than in untreated samples. The fermentations done with treated grapes allowed starter cultures to better implant in the must, although a larger anthocyanin loss (up to 93%) and an increase in hue values (1 unit) towards more yellow hues were observed for treated grapes. The development of biomass was larger in musts from treated grapes. The profile of volatile compounds and oenological parameters reveals that fermentations carried out with untreated grapes are prone to deviations from native microbiota (e.g., production of lactic acid). Finally, no severe damage on the skin was observed with the AFM on treated grapes.
31
Martín-García, Alba, Aitor Balmaseda, Albert Bordons e Cristina Reguant. "Effect of the inoculation strategy of non-Saccharomyces yeasts on wine malolactic fermentation". OENO One 54, n. 1 (29 febbraio 2020): 101–8. http://dx.doi.org/10.20870/oeno-one.2020.54.1.2906.
Testo completoAbstract (sommario):
Interest in some non-Saccharomyces yeasts has increased recently, because they have been associated with an improvement in wine quality. Nevertheless, little attention has been paid to the effect that the use of these yeasts may have on malolactic fermentation (MLF). In this study, the strains Torulaspora delbrueckii Biodiva and Metschnikowia pulcherrima Flavia were evaluated by co-inoculation and sequential fermentation with S. cerevisiae QA23. A fermentation with S. cerevisiae as a single starter was also performed as a control, then MLF was performed inoculating Oenococcus oeni PSU-1 in all wines. Finally, the wines obtained after alcoholic fermentation and MLF were characterised. The results of the coinoculated fermentations were similar to those of the S. cerevisiae control fermentations. Nevertheless, significant differences were observed in sequential fermentations in terms of lower content of acetic, L-malic and succinic acids. These differences were particularly noticeable in fermentations carried out with T. delbrueckii.
32
Luzzini, Giovanni, Davide Slaghenaufi e Maurizio Ugliano. "Volatile Compounds in Monovarietal Wines of Two Amarone Della Valpolicella Terroirs: Chemical and Sensory Impact of Grape Variety and Origin, Yeast Strain and Spontaneous Fermentation". Foods 10, n. 10 (15 ottobre 2021): 2474. http://dx.doi.org/10.3390/foods10102474.
Testo completoAbstract (sommario):
Aroma profiles of withered Corvina and Corvinone wines from two different Valpolicella terroirs were investigated in relationship to yeast strain and use of spontaneous fermentation. The results indicated that volatile chemical differences between wines were mainly driven by grape origin, which was associated with distinctive compositional profiles. Wine content in terpenes, norisoprenoids, benzenoids and C6 alcohols, as well as some fermentative esters, were indeed significantly affected by grape origin. Conversely, yeast strain influence was mainly associated with fermentation-derived esters. Sensory analysis, besides confirming the major role of grape origin as driver of wine differentiation, indicated that spontaneous fermentations reduced the sensory differences associated with grape origin and variety, mainly due to high content of acetic acid and ethyl acetate.
33
Bencresciuto, Grazia Federica, Claudio Mandalà, Carmela Anna Migliori, Lucia Giansante, Luciana Di Giacinto e Laura Bardi. "Microbial Biotechnologies to Produce Biodiesel and Biolubricants from Dairy Effluents". Fermentation 10, n. 6 (24 maggio 2024): 278. http://dx.doi.org/10.3390/fermentation10060278.
Testo completoAbstract (sommario):
The shift from fossil fuels to renewable energy sources is crucial in addressing environmental challenges. Vegetable oils have been focused on as the main potential source for biodiesel and biolubricant production. However, due to their fatty acid (FA) composition they are characterized by low stability to oxidation and variable viscosity. Single-cell oils (SCOs) from oleaginous microorganisms are a possible alternative to vegetable oils: their composition is more suitable, and it can further be improved by controlling the fermentation’s physiological conditions. In the present study, the production of SCOs with targeted technological properties from Lipomyces starkeyi in fermentation under controlled temperatures was assessed. A dairy effluent (scotta) was used as the fermentation substrate to improve the economic sustainability of the process. Batch aerobic fermentations were carried out in a fermenter at two different temperatures (25 °C and 30 °C). The fermentation yields and SCO FA profiles were analyzed. The highest yields of biomass (9.76 g L−1) and microbial oil (1.83 g L−1) were obtained from fermentations carried out at 30 °C. Furthermore, a significantly lower content (46% vs. 55%) of unsaturated FAs and higher content (11% vs. 1.5%) of shorter-chain saturated FAs, with myristic acid almost matching stearic acid, were detected at 30 °C in comparison to 25 °C. Very low peroxide values were also found (0.14 meq O2 kg−1 at 30 °C and 0 meq O2 kg−1 at 25 °C). These results indicate that these SCOs were highly oxidation-resistant, and that a higher fermentation temperature improves their oxidative stability and tribophysical features. The biodiesels’ technological properties, calculated from the FA composition, were within the limits of both U.S. standards and E.U. regulations. Then, SCOs produced from L. starkeyi by fermentation of dairy effluents carried out under controlled temperature can be considered a suitable alternative to vegetable oils to produce biodiesel and biolubricants.
34
Barrón-Álvarez, Nayeli, Lilia Arely Prado-Barragán, María de los Ángeles Fortis-Barrera e Francisco Javier Alarcon-Aguilar. "Fermentation of the Cucurbita ficifolia Fruit Juice: Its Antioxidant Activity and Effects on the Glycemia". Beverages 8, n. 3 (7 settembre 2022): 55. http://dx.doi.org/10.3390/beverages8030055.
Testo completoAbstract (sommario):
Cucurbita ficifolia is an edible plant whose fruits have hypoglycemic, anti-inflammatory, and antioxidant activities. Fermentation might improve these properties. This research aims to perform and characterize its fermentation in native and induced conditions with Lactobacillus plantarum (Lp) and evaluate its antioxidant activity and effect on glycemia. Fresh juice from mature fruits was characterized. One portion of this juice was spontaneously left to ferment (native fermentation), and the other was inoculated with Lp (controlled fermentation). Fermentation was monitored each 8 h by 56 h to measure microbial growth, pH, acidity, sugars, soluble protein, polyphenols and flavonoids, antioxidant activity, and effects on glycemia. In native fermentation, the growth of total microorganisms increased up to 32 h, decreasing at the end of the process. In Lp fermentation, total microorganisms increased until 16 h to stay constant at the end, with a predominance of Lp. The pH and the sugars decreased in the two fermentations, while polyphenol and flavonoid increased. In spontaneous fermentation, these changes were lesser. Both fermentations, like fresh juice, preserve functional properties (antioxidant, alpha-glucosidase inhibition, and hypoglycemia). The fermentation of this juice with Lp may develop functional beverages, which is significant due to its consumption as an edible fruit with medicinal properties.
35
Chen, Shuoyu, Fanxin Zhang, Edwin Ananta, Jeroen André Muller, Youyun Liang, Yuan Kun Lee e Shao-Quan Liu. "Co-Inoculation of Latilactobacillus sakei with Pichia kluyveri or Saccharomyces boulardii Improves Flavour Compound Profiles of Salt-Free Fermented Wheat Gluten". Fermentation 10, n. 2 (24 gennaio 2024): 75. http://dx.doi.org/10.3390/fermentation10020075.
Testo completoAbstract (sommario):
A wheat gluten fermentation process with the inoculation of different microorganisms under salt-free conditions has the potential to produce varying flavour profiles. As research on the co-fermentation of yeasts and lactic acid bacteria (LAB) in salt-free wheat gluten fermentation is scarce, the current work studied the flavour impact on fermented wheat gluten by the co-inoculation of Latilactobacillus sakei with one yeast (Saccharomyces boulardii or Pichia kluyveri). The results showed that similar glucose and organic acid levels were detected, but early death of yeasts was observed during liquid-state fermentation (LSF) in co-fermentations. The concentrations of most free amino acids were comparable. Volatile compound analysis showed synergistic effects in co-cultured fermentations on the production of certain compounds such as isoamyl acetate. Principal component analysis revealed clear differences in volatile profiles between co-fermentation and single-strain fermentation. Therefore, a fermented sauce produced by co-inoculating LAB and yeast with a new and fruitier flavour was developed.
36
Canonico, Laura, Alice Agarbati, Francesca Comitini e Maurizio Ciani. "Assessment of Spontaneous Fermentation and Non-Saccharomyces Sequential Fermentation in Verdicchio Wine at Winery Scale". Beverages 8, n. 3 (19 agosto 2022): 49. http://dx.doi.org/10.3390/beverages8030049.
Testo completoAbstract (sommario):
The use of non-Saccharomyces yeasts in sequential fermentation is a suitable biotechnological process to provide specific oenological characteristics and to increase the complexity of wines. In this work, selected strains of Lachancea thermotolerans and Starmerella bombicola were used in sequential fermentations with Saccharomyces cerevisiae and compared with spontaneous and pure S. cerevisiae fermentation trials in Verdicchio grape juice. Torulaspora delbrueckii together with the other two non-Saccharomyces strains (L. thermotolerans, S. bombicola) in multi-sequential fermentations was also evaluated. Wines, obtained under winery vinification conditions, were evaluated for their analytical and sensorial profile. The results indicated that each fermentation gave peculiar analytical and aromatic features of the final wine. L. thermotolerans trials are characterized by an increase of total acidity, higher alcohols and monoterpenes as well as citric and herbal notes. S. bombicola trials showed a general significantly high concentration of phenylethyl acetate and hexyl acetate and a softness sensation while multi-sequential fermentations showed a balanced profile. Spontaneous fermentation was characterized by the production of acetate esters (ethyl acetate and isoamyl acetate), citrus and herbal notes, and tannicity. The overall results indicate that multi-starter fermentations could be a promising tool tailored to the desired features of different Verdicchio wine styles.
37
Henderson, Clark M., Michelle Lozada-Contreras, Vladimir Jiranek, Marjorie L. Longo e David E. Block. "Ethanol Production and Maximum Cell Growth Are Highly Correlated with Membrane Lipid Composition during Fermentation as Determined by Lipidomic Analysis of 22 Saccharomyces cerevisiae Strains". Applied and Environmental Microbiology 79, n. 1 (12 ottobre 2012): 91–104. http://dx.doi.org/10.1128/aem.02670-12.
Testo completoAbstract (sommario):
ABSTRACTOptimizing ethanol yield during fermentation is important for efficient production of fuel alcohol, as well as wine and other alcoholic beverages. However, increasing ethanol concentrations during fermentation can create problems that result in arrested or sluggish sugar-to-ethanol conversion. The fundamental cellular basis for these problem fermentations, however, is not well understood. Small-scale fermentations were performed in a synthetic grape must using 22 industrialSaccharomyces cerevisiaestrains (primarily wine strains) with various degrees of ethanol tolerance to assess the correlation between lipid composition and fermentation kinetic parameters. Lipids were extracted at several fermentation time points representing different growth phases of the yeast to quantitatively analyze phospholipids and ergosterol utilizing atmospheric pressure ionization-mass spectrometry methods. Lipid profiling of individual fermentations indicated that yeast lipid class profiles do not shift dramatically in composition over the course of fermentation. Multivariate statistical analysis of the data was performed using partial least-squares linear regression modeling to correlate lipid composition data with fermentation kinetic data. The results indicate a strong correlation (R2= 0.91) between the overall lipid composition and the final ethanol concentration (wt/wt), an indicator of strain ethanol tolerance. One potential component of ethanol tolerance, the maximum yeast cell concentration, was also found to be a strong function of lipid composition (R2= 0.97). Specifically, strains unable to complete fermentation were associated with high phosphatidylinositol levels early in fermentation. Yeast strains that achieved the highest cell densities and ethanol concentrations were positively correlated with phosphatidylcholine species similar to those known to decrease the perturbing effects of ethanol in model membrane systems.
38
Henderson, Clark M., Wade F. Zeno, Larry A. Lerno, Marjorie L. Longo e David E. Block. "Fermentation Temperature Modulates Phosphatidylethanolamine and Phosphatidylinositol Levels in the Cell Membrane of Saccharomyces cerevisiae". Applied and Environmental Microbiology 79, n. 17 (28 giugno 2013): 5345–56. http://dx.doi.org/10.1128/aem.01144-13.
Testo completoAbstract (sommario):
ABSTRACTDuring alcoholic fermentation,Saccharomyces cerevisiaeis exposed to a host of environmental and physiological stresses. Extremes of fermentation temperature have previously been demonstrated to induce fermentation arrest under growth conditions that would otherwise result in complete sugar utilization at “normal” temperatures and nutrient levels. Fermentations were carried out at 15°C, 25°C, and 35°C in a defined high-sugar medium using threeSaccharomyces cerevisiaestrains with diverse fermentation characteristics. The lipid composition of these strains was analyzed at two fermentation stages, when ethanol levels were low early in stationary phase and in late stationary phase at high ethanol concentrations. Several lipids exhibited dramatic differences in membrane concentration in a temperature-dependent manner. Principal component analysis (PCA) was used as a tool to elucidate correlations between specific lipid species and fermentation temperature for each yeast strain. Fermentations carried out at 35°C exhibited very high concentrations of several phosphatidylinositol species, whereas at 15°C these yeast strains exhibited higher levels of phosphatidylethanolamine and phosphatidylcholine species with medium-chain fatty acids. Furthermore, membrane concentrations of ergosterol were highest in the yeast strain that experienced stuck fermentations at all three temperatures. Fluorescence anisotropy measurements of yeast cell membrane fluidity during fermentation were carried out using the lipophilic fluorophore diphenylhexatriene. These measurements demonstrate that the changes in the lipid composition of these yeast strains across the range of fermentation temperatures used in this study did not significantly affect cell membrane fluidity. However, the results from this study indicate that fermentingS. cerevisiaemodulates its membrane lipid composition in a temperature-dependent manner.
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van Holst Pellekaan, Nicholas, Michelle E. Walker, Tommaso L. Watson e Vladimir Jiranek. "‘TeeBot’: A High Throughput Robotic Fermentation and Sampling System". Fermentation 7, n. 4 (24 settembre 2021): 205. http://dx.doi.org/10.3390/fermentation7040205.
Testo completoAbstract (sommario):
When fermentation research requires the comparison of many strains or conditions, the major bottleneck is a technical one. Microplate approaches are not able to produce representative fermentative performance due to their inability to truly operate anaerobically, whilst more traditional methods do not facilitate sample density sufficient to assess enough candidates to be considered even medium throughput. Two robotic platforms have been developed that address these technological shortfalls. Both are built on commercially available liquid handling platforms fitted with custom labware. Results are presented detailing fermentation performance as compared to current best practice, i.e., shake flasks fitted with airlocks and sideports. The ‘TeeBot’ is capable sampling from 96 or 384 fermentations in 100 mL or 30 mL volumes, respectively, with airlock sealing and minimal headspace. Sampling and downstream analysis are facilitated by automated liquid handling, use of 96-well sample plate format and temporary cryo-storage (<0 °C).
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Mills, David A., Eric A. Johannsen e Luca Cocolin. "Yeast Diversity and Persistence in Botrytis-Affected Wine Fermentations". Applied and Environmental Microbiology 68, n. 10 (ottobre 2002): 4884–93. http://dx.doi.org/10.1128/aem.68.10.4884-4893.2002.
Testo completoAbstract (sommario):
ABSTRACT Culture-dependent and -independent methods were used to examine the yeast diversity present in botrytis-affected (“botrytized”) wine fermentations carried out at high (∼30°C) and ambient (∼20°C) temperatures. Fermentations at both temperatures possessed similar populations of Saccharomyces, Hanseniaspora, Pichia, Metschnikowia, Kluyveromyces, and Candida species. However, higher populations of non-Saccharomyces yeasts persisted in ambient-temperature fermentations, with Candida and, to a lesser extent, Kluyveromyces species remaining long after the fermentation was dominated by Saccharomyces. In general, denaturing gradient gel electrophoresis profiles of yeast ribosomal DNA or rRNA amplified from the fermentation samples correlated well with the plating data. The direct molecular methods also revealed a Hanseniaspora osmophila population not identified in the plating analysis. rRNA analysis also indicated a large population (>106 cells per ml) of a nonculturable Candida strain in the high-temperature fermentation. Monoculture analysis of the Candida isolate indicated an extreme fructophilic phenotype and correlated with an increased glucose/fructose ratio in fermentations containing higher populations of Candida. Analysis of wine fermentation microbial ecology by using both culture-dependent and -independent methods reveals the complexity of yeast interactions enriched during spontaneous fermentations.
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Zhang, Da Wei, Wen Bin Dong, Dan Zhang, Lei Jin, Jie Zhang, De Ming Li e Hui Dong Li. "Simultaneous and Sequential Fermentations with Saccharomyces cerevisiae DJ02 and Lactobacliius acidophilus WS in Pear Wine". Advanced Materials Research 317-319 (agosto 2011): 2388–92. http://dx.doi.org/10.4028/www.scientific.net/amr.317-319.2388.
Testo completoAbstract (sommario):
The two controlled inoculation procedures of simultaneous and sequential fermentations with Saccharomyces Cerevisiae DJ02 and Lactobacliius acidophilus WS were studied in pear wine. The sugar consumption and ethanol product were delayed in the course of simultaneous fermentation contrary to the single fermentation. However in the sequential fermentation the effect was less than the simultaneous fermentation. In this work the function of malic acid degradation in the sequential fermentation was better than the simultaneous fermentation. The pH value of the pear wine came to 3.9 after the sequential fermentation. The change tendency of the yeast population after adding Lactobacliius acidophilus WS was similar to the yeast single fermentation in the simultaneous and sequential fermentation. But the cell population was went down in the course of the fermentation. The population of Lactobacliius acidophilus WS in the course of the two kinds of fermentation methods showed no significantly differences.
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Monte Alegre, Ranulfo, Maurício Rigo e Inés Joekes. "Ethanol fermentation of a diluted molasses medium by Saccharomyces cerevisiae immobilized on chrysotile". Brazilian Archives of Biology and Technology 46, n. 4 (dicembre 2003): 751–57. http://dx.doi.org/10.1590/s1516-89132003000400031.
Testo completoAbstract (sommario):
In this work, the catalytic role of chrysotile support on the acceleration of alcoholic fermentation under non-aseptic conditions by Saccharomyces cerevisiae was investigated. The fermentation medium employed consisted only of diluted sugar-cane molasses. In the batch fermentations process with immobilized yeasts, the initial rate of CO2 production increased roughly 27 % during the first 30 minutes, compared to systems containing no chrysotile. A study of continuous alcoholic fermentation with chrysotile in the reactor bed showed a higher ethanol production rate at the different dilution rates investigated compared to similar fermentations without chrysotile.
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Liu, Jing Hui, Wi Di Zhang, Fang Yin, Jing Liu, Xing Ling Zhao, Shi Qing Liu, Ling Xu, Yu Bao Chen e Hong Yang. "Effects of Different Treatments on Properties of Biogas Fermentation with Ginger Skin". Advanced Materials Research 953-954 (giugno 2014): 284–89. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.284.
Testo completoAbstract (sommario):
In order to obtain gas potential and characteristics of ginger skin in biogas fermentation as raw material, and explore effect of different treatments on properties of biogas fermentation with ginger skin. At the temperature of 30°C, biogas fermentations with ginger skin were treated in two ways (natural decay and mixed with pig manure). Experiments were respectively set five different treatments (direct fermentation, natural decay, adding pig manure after natural decay (TS content of pig manure / TS content of ginger skin were respectively 1:1, 2:1 and 3:1)). The results showed gas potential of ginger skin and total gas production were respectively 118.08ml/gTS and 320ml, after the 11th day, the fermentation was in a serious acidification, as a result of stopping gas production. The fermentations with ginger skin which went through natural decay and adding pig manure after natural decay can both eliminate acidification which caused by use of ginger skin directly, and conduce to the fermentation with ginger skin. The fermentation with ginger skin which went through natural decay had higher degradation rate of TS, total gas production, TS gas potential and methane content than fermentation with ginger skin directly.
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Mecca, Debora, Santiago Benito, Beata Beisert, Silvia Brezina, Stefanie Fritsch, Heike Semmler e Doris Rauhut. "Influence of Nutrient Supplementation on Torulaspora Delbrueckii Wine Fermentation Aroma". Fermentation 6, n. 1 (22 marzo 2020): 35. http://dx.doi.org/10.3390/fermentation6010035.
Testo completoAbstract (sommario):
This study was performed with the aim of characterizing the fermentative performance of three commercial strains of Torulaspora delbrueckii and their impact on the production of volatile and non-volatile compounds. Laboratory-scale single culture fermentations were performed using a commercial white grape juice. The addition of commercial nutrient products enabled us to test the yeasts under two different nutrient conditions. The addition of nutrients promoted fermentation intensity from 9% to 20 % with significant differences (p < 0.05) among the strains tested. The strain diversity together with the nutrient availability influenced the production of volatile compounds.
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Iram, Attia, Ali Ozcan, Irfan Turhan e Ali Demirci. "Production of Value-Added Products as Food Ingredients via Microbial Fermentation". Processes 11, n. 6 (3 giugno 2023): 1715. http://dx.doi.org/10.3390/pr11061715.
Testo completoAbstract (sommario):
Humankind has been unknowingly utilizing food fermentations since the first creation of bread, cheese, and other basic foods. Since the beginning of the last century, microbial fermentation has been extensively utilized for production of commodity chemicals. It has also gained substantial interest in recent decades due to its underlying applications in the preparation of natural and safe food ingredients including enzymes, antimicrobial agents, vitamins, organic acids, sweeteners, stabilizers, emulsifiers, oligosaccharides, amino acids, and thickening agents. In addition, some novel food ingredients that were conventionally made from some other sources such as plant tissue cultures or animals are now being introduced in the industry as ‘fermentation products.’ Some examples of such novel fermentation food ingredients include flavonoids, cultured meat products, food colorants, antioxidants, lipids, and fatty acids. This review summarizes some of the most prominent food ingredients and novel fermentation food products currently being produced via microbial fermentation as well as the strategies to enhance such fermentation processes. Additionally, economical feedstocks are discussed with their potential to be converted into value-added products with the help of microbial fermentations.
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Coleman, Matthew C., Russell Fish e David E. Block. "Temperature-Dependent Kinetic Model for Nitrogen-Limited Wine Fermentations". Applied and Environmental Microbiology 73, n. 18 (6 luglio 2007): 5875–84. http://dx.doi.org/10.1128/aem.00670-07.
Testo completoAbstract (sommario):
ABSTRACT A physical and mathematical model for wine fermentation kinetics was adapted to include the influence of temperature, perhaps the most critical factor influencing fermentation kinetics. The model was based on flask-scale white wine fermentations at different temperatures (11 to 35°C) and different initial concentrations of sugar (265 to 300 g/liter) and nitrogen (70 to 350 mg N/liter). The results show that fermentation temperature and inadequate levels of nitrogen will cause stuck or sluggish fermentations. Model parameters representing cell growth rate, sugar utilization rate, and the inactivation rate of cells in the presence of ethanol are highly temperature dependent. All other variables (yield coefficient of cell mass to utilized nitrogen, yield coefficient of ethanol to utilized sugar, Monod constant for nitrogen-limited growth, and Michaelis-Menten-type constant for sugar transport) were determined to vary insignificantly with temperature. The resulting mathematical model accurately predicts the observed wine fermentation kinetics with respect to different temperatures and different initial conditions, including data from fermentations not used for model development. This is the first wine fermentation model that accurately predicts a transition from sluggish to normal to stuck fermentations as temperature increases from 11 to 35°C. Furthermore, this comprehensive model provides insight into combined effects of time, temperature, and ethanol concentration on yeast (Saccharomyces cerevisiae) activity and physiology.
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Deed, Rebecca C., e Lisa I. Pilkington. "Lifestyle, Lineage, and Geographical Origin Influence Temperature-Dependent Phenotypic Variation across Yeast Strains during Wine Fermentation". Microorganisms 8, n. 9 (7 settembre 2020): 1367. http://dx.doi.org/10.3390/microorganisms8091367.
Testo completoAbstract (sommario):
Saccharomyces cerevisiae yeasts are a diverse group of single-celled eukaryotes with tremendous phenotypic variation in fermentation efficiency, particularly at different temperatures. Yeast can be categorized into subsets based on lifestyle (Clinical, Fermentation, Laboratory, and Wild), genetic lineage (Malaysian, Mosaic, North American, Sake, West African, and Wine), and geographical origin (Africa, Americas, Asia, Europe, and Oceania) to start to understand their ecology; however, little is known regarding the extent to which these groupings drive S. cerevisiae fermentative ability in grape juice at different fermentation temperatures. To investigate the response of yeast within the different subsets, we quantified fermentation performance in grape juice by measuring the lag time, maximal fermentation rate (Vmax), and fermentation finishing efficiency of 34 genetically diverse S. cerevisiae strains in grape juice at five environmentally and industrially relevant temperatures (10, 15, 20, 25, and 30 °C). Extensive multivariate analysis was applied to determine the effects of lifestyle, lineage, geographical origin, strain, and temperature on yeast fermentation phenotypes. We show that fermentation capability is inherent to S. cerevisiae and that all factors are important in shaping strain fermentative ability, with temperature having the greatest impact, and geographical origin playing a lesser role than lifestyle or genetic lineage.
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del Fresno, Juan Manuel, Carlos Escott, Francisco Carrau, José Enrique Herbert-Pucheta, Cristian Vaquero, Carmen González e Antonio Morata. "Improving Aroma Complexity with Hanseniaspora spp.: Terpenes, Acetate Esters, and Safranal". Fermentation 8, n. 11 (19 novembre 2022): 654. http://dx.doi.org/10.3390/fermentation8110654.
Testo completoAbstract (sommario):
Hanseniaspora vineae and Hanseniaspora opuntiae are apiculate yeasts normally found on the skins of ripe grapes and at the beginning of alcoholic fermentation. Several studies have reported that these species can provide interesting sensory characteristics to wine by contributing high levels of acetate esters and can increase the mouthfeel and body of wines. The present work aims to evaluate the use of these two species sequentially with Saccharomyces cerevisiae to improve the sensory profile of Albillo Mayor white wines. The fermentations were carried out in triplicate in 150 L stainless steel barrels. At the end of the alcoholic fermentation polysaccharides, colour, and an extensive study of the aromatic profiles were measured. Results showed up to 1.55 times higher content of 2-phenylethanol in H. opuntiae wines and up to three times higher concentration of fermentative esters in H. vineae wines than in the controls. Interestingly, it should be noted that the compound safranal was identified only in the H. vineae wines. These results indicated that the species studied are an interesting bio-tool to improve the aromatic profile of Albillo Mayor white wines. A novel non-targeted NMR-based metabolomics approach is proposed as a tool for optimising wine productions with standard and sequential fermentation schemes using apiculate yeast strains due to its discriminant capacity to differentiate fine features between wine samples from the identical geographical origin and grape variety but diverse fermentations or vintages.
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Luo, Hui Bo, Chun Hui Wei e Xian Ling Yuan. "Study on the Metabolites of a Bacteria Strain Producing Esterifying Synthetase". Advanced Materials Research 550-553 (luglio 2012): 1080–84. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.1080.
Testo completoAbstract (sommario):
The metabolites characteristics of a bacteria producing esterifying synthetase in different fermentation conditions were studied. A bacteria strain producing esterifying enzyme was isolated from Luzhou-flavor Daqu and it was identified by Biolog Microbes automated identification System. Fermentation conditions such as fermentation time, fermentation initial pH and fermentation temperature were changed. The fermentatiom broth was extracted by ethanol and analyzed by GC-MS. The results showed that the strain was Geobacillus thermoglucosidasius. With the prolonging of fermentation time, methanol and various higher alcohols were gradually decreased and even disappeared, but the esters were gradually increased. With the rise of fermentation initial pH, the acids were decreased. When initial pH was 7.5, more esters were produced, but some metabolites were not changed with the initial pH of fermentation, such as acetic acid, acetaldehyde, 3-methyl butanol and 3-Hydroxy-2-butanone etc. With the increase of fermentation temperature, the alcohols and acids kinds increased. When the fermentation temperature was 35°C, the more esters were produced.
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Boll, Matthias, Johannes W. Kung, Ulrich Ermler, Berta M. Martins e Wolfgang Buckel. "Fermentative Cyclohexane Carboxylate Formation in Syntrophus aciditrophicus". Journal of Molecular Microbiology and Biotechnology 26, n. 1-3 (2016): 165–79. http://dx.doi.org/10.1159/000440881.
Testo completoAbstract (sommario):
Short-chain fatty acids such as acetic, propionic, butyric or lactic acids are typical primary fermentation products in the anaerobic feeding chain. Fifteen years ago, a novel fermentation type was discovered in the obligately anaerobic Deltaproteobacterium <i>Syntrophus aciditrophicus</i>. During fermentative growth with crotonate and/or benzoate, acetate is formed in the oxidative branch and cyclohexane carboxylate in the reductive branch. In both cases cyclohexa-1,5-diene-1-carboxyl-CoA (Ch1,5CoA) is a central intermediate that is either formed by a class II benzoyl-CoA reductase (fermentation of benzoate) or by reverse reactions of the benzoyl-CoA degradation pathway (fermentation of crotonate). Here, we summarize the current knowledge of the enzymology involved in fermentations yielding cyclohexane carboxylate as an excreted product. The characteristic enzymes involved are two acyl-CoA dehydrogenases specifically acting on Ch1,5CoA and cyclohex-1-ene-1-carboxyl-CoA. Both enzymes are also employed during the syntrophic growth of <i>S. aciditrophicus</i> with cyclohexane carboxylate as the carbon source in coculture with a methanogen. An investigation of anabolic pathways in <i>S. aciditrophicus</i> revealed a rather unusual pathway for glutamate synthesis involving a <i>Re</i>-citrate synthase. Future work has to address the unresolved question concerning which components are involved in reoxidation of the NADH formed in the oxidative branch of the unique cyclohexane carboxylate fermentation pathway in <i>S. aciditrophicus</i>.