Usporedba aromatskih komponenti vina dobivenih fermentacijom Saccharomyces paradoxus i Saccharomyces cerevisiae sojeva

The aim of this study is to determine specific enological characteristics of Saccharomyces paradoxus species, potential differences in production of volatile components between Saccharomyces paradoxus and Saccharomyces cerevisiae strains and their influence on final wine quality. Samples of young wine were analysed for higher alcohols, fatty acids and volatile esters. At the same time wines were subjected to sensory evaluation. The results showed a notable influence of Saccharomyces paradoxus strain RO88 on chemical and sensory properties of Gewürtztraminer wine and indicated some differences between Saccharomyces paradoxus and Saccharomyces cerevisiae species.Cilj je ovog istraživanja utvrditi specifične enološke značajke vrste Saccharomyces paradoxus, potencijalne različitosti između vrste Saccharomyces paradoxus i Saccharomyces cerevisiae u sintezi hlapljivih komponenti te njihov utjecaj na kakvoću vina. Analizirane su koncentracije viših alkohola, masnih kiselina i hlapljivih estera, a vina su i senzorno ocijenjena. Rezultati su pokazali bitan utjecaj soja Saccharomyces paradoxus RO88 na kemijski sastav i senzorna svojstva vina Traminac te su upozorili i na razlike izme|u vrsta Saccharomyces paradoxus i Saccharomyces cerevisiae

Introducing a new breed of wine yeast: interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast and Saccharomyces mikatae

Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentation environs. While commercially available wine yeast strains provide consistent and reliable fermentations, wines produced using single inocula are thought to lack the sensory complexity and rounded palate structure obtained from spontaneous fermentations. In contrast, interspecific yeast hybrids have the potential to deliver increased complexity to wine sensory properties and alternative wine styles through the formation of novel, and wider ranging, yeast volatile fermentation metabolite profiles, whilst maintaining the robustness of the wine yeast parent. Screening of newly generated hybrids from a cross between a S. cerevisiae wine yeast and S. mikatae (closely-related but ecologically distant members of the Saccharomyces sensu stricto clade), has identified progeny with robust fermentation properties and winemaking potential. Chemical analysis showed that, relative to the S. cerevisiae wine yeast parent, hybrids produced wines with different concentrations of volatile metabolites that are known to contribute to wine flavour and aroma, including flavour compounds associated with non-Saccharomyces species. The new S. cerevisiae x S. mikatae hybrids have the potential to produce complex wines akin to products of spontaneous fermentation while giving winemakers the safeguard of an inoculated ferment.Jennifer R. Bellon, Frank Schmid, Dimitra L. Capone, Barbara L. Dunn, Paul J. Chamber

Mitochondrial DNA and temperature tolerance in lager yeasts

A growing body of research suggests that the mitochondrial genome (mtDNA) is important for temperature adaptation. In the yeast genus Saccharomyces, species have diverged in temperature tolerance, driving their use in high- or low-temperature fermentations. Here, we experimentally test the role of mtDNA in temperature tolerance in synthetic and industrial hybrids (Saccharomyces cerevisiae × Saccharomyces eubayanus or Saccharomyces pastorianus), which cold-brew lager beer. We find that the relative temperature tolerances of hybrids correspond to the parent donating mtDNA, allowing us to modulate lager strain temperature preferences. The strong influence of mitotype on the temperature tolerance of otherwise identical hybrid strains provides support for the mitochondrial climactic adaptation hypothesis in yeasts and demonstrates how mitotype has influenced the world’s most commonly fermented beverage.This work was supported by the USDA National Institute of Food and Agriculture (Hatch project no. 1003258), the NSF (grant no. DEB-1253634), and in part by the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science; nos. DE-SC0018409 and DE-FC02-07ER64494). E.P.B. was supported by a Louis and Elsa Thomsen Wisconsin Distinguished Graduate Fellowship. C.T.H. is a Pew Scholar in the Biomedical Sciences and a Vilas Faculty Early Career Investigator, supported by the Pew Charitable Trusts and the Vilas Trust Estate. D.P. is a Marie Sklodowska-Curie fellow of the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 747775). J.C.F. was supported by the NIH (no. GM080669)Peer Reviewe

The geographic distribution of saccharomyces cerevisiae isolates within three Italian neighboring winemaking regions reveals strong differences in yeast abundance, genetic diversity and industrial strain dissemination

In recent years the interest for natural fermentations has been re-evaluated in terms of increasing the wine terroir and managing more sustainable winemaking practices. Therefore, the level of yeast genetic variability and the abundance of Saccharomyces cerevisiae native populations in vineyard are becoming more and more crucial at both ecological and technological level. Among the factors that can influence the strain diversity, the commercial starter release that accidentally occur in the environment around the winery, has to be considered. In this study we led a wide scale investigation of S. cerevisiae genetic diversity and population structure in the vineyards of three neighboring winemaking regions of Protected Appellation of Origin, in North-East of Italy. Combining mtDNA RFLP and microsatellite markers analyses we evaluated 634 grape samples collected over 3 years. We could detect major differences in the presence of S. cerevisiae yeasts, according to the winemaking region. The population structures revealed specificities of yeast microbiota at vineyard scale, with a relative Appellation of Origin area homogeneity, and transition zones suggesting a geographic differentiation. Surprisingly, we found a widespread industrial yeast dissemination that was very high in the areas where the native yeast abundance was low. Although geographical distance is a key element involved in strain distribution, the high presence of industrial strains in vineyard reduced the differences between populations. This finding indicates that industrial yeast diffusion it is a real emergency and their presence strongly interferes with the natural yeast microbiota

Saccharomyces cerevisiae in the production of fermented beverages

Alcoholic beverages are produced following the fermentation of sugars by yeasts, mainly (but not exclusively) strains of the species, Saccharomyces cerevisiae. The sugary starting materials may emanate from cereal starches (which require enzymatic pre‐hydrolysis) in the case of beers and whiskies, sucrose‐rich plants (molasses or sugar juice from sugarcane) in the case of rums, or from fruits (which do not require pre‐hydrolysis) in the case of wines and brandies. In the presence of sugars, together with other essential nutrients such as amino acids, minerals and vitamins, S. cerevisiae will conduct fermentative metabolism to ethanol and carbon dioxide (as the primary fermentation metabolites) as the cells strive to make energy and regenerate the coenzyme NAD+ under anaerobic conditions. Yeasts will also produce numerous secondary metabolites which act as important beverage flavour congeners, including higher alcohols, esters, carbonyls and sulphur compounds. These are very important in dictating the final flavour and aroma characteristics of beverages such as beer and wine, but also in distilled beverages such as whisky, rum and brandy. Therefore, yeasts are of vital importance in providing the alcohol content and the sensory profiles of beverages. This Introductory Chapter reviews, in general, the growth, physiology and metabolism of S. cerevisiae in alcoholic beverage fermentations

Kinetics of invertase synthesis by Saccharomyces cerevisiae in synthetic medium

Present investigation deals with optimization of appropriate substrate concentration and incubation temperature both for growth of Saccharomyces cerevisiae and invertase production. Submerged fermentation technique was employed in the present study. The maximal production of invertase during the course of study was achieved after 48 h of incubation using initial sucrose concentration, 15.0 g l-1. The sugar consumption and dry cell mass were also examined. Data was subjected to kinetic analysis and on the basis of kinetic parameters such as Yp/x (amount of enzyme produced mg-1 cell mass), Yp/s (amount of enzyme produced mg-1 sugar consumed), Yx/s (mg cells mg-1 substrate consumed), Ys/x (mg sugar consumed mg-1 cell mass produced), qp (Amount of enzyme produced mg-1 sugar consumed h-1), qs (mg mg-1 cells h-1), qx (mg cells mg-1 sugar consumed h-1), µ (mg cells produced h-1), it was found that temperature had a direct influence both on substrate consumption and synthesis of enzyme. Similarly, higher concentrations of sucrose in fermentation medium induced catabolite repression of yeast invertase

PENGARUH VARIASI MASSA RAGI SACCHAROMYCES CEREVISIAE DAN LAMA FERMENTASI TERHADAP DENSITAS DAN RENDEMEN BIOETANOL ALANG-ALANG (Imperata Cy-lindrica)

Ketersediaan energi fosil dalam penggunaan bahan bakar semakin menipis dan tingkat residu yang dihasilkan semakin menigkat, sehingga diperlukan sumber energi alternatif untuk menunjang kebutuhan energi salah satunya bioetanol. Alang- alang (Imperata cylindrica) memiliki kandungan selulosa sebanyak 40,22% dapat digunakan sebagai bahan dasar bioetanol dengan bantuan Saccharomyces cerevisiae pengubah glukosa menjadi etanol. Tujuan penelitian ini untuk menganalisis karakteristik bioetanol berdasarkan densitas dan persen rendemen bioetanol dengan variasi massa ragi roti Saccharomyces cerevisiae dan waktu fermentasi. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL), dengan 4 perlakuan dan 3 kali ulangan. Jumlah takaran larutan untuk setiap perlakuan adalah 100 ml. Nilai densitas tertinggi pada perlakuan 4 massa   roti Saccharomyces cerevisiae 15 gram dengan lama fermentasi 6 hari sebesar 0.9041 g/ml, nilai densitas terendah pada perlakuan 1 massa ragi roti Saccharomyces cerevisiae 10 gram dan lama fermentasi 3 hari sebesar 0,9340 g/ml. Persen rendemen tertinggi diperoleh dari perlakuan 4 massa ragi roti Saccharomyces cerevisiae 15 gram dan lama fermentasi 6 hari sebanyak 23,11% dan persen rendemen terendah pada perlakuan 1 dengan massa ragi roti Saccharomyces cerevisiae 10 gram dan lama fermentasi 3 hari sebesar 17,90%. Hasil penelitian menunjukkan ada pengaruh variasi konsentrasi  Saccharomyces cerevisiae dan lama fermentasi terhadap nilai densitas dan persen rendemen

Population genomics of domestic and wild yeasts

The natural genetics of an organism is determined by the distribution of sequences of its genome. Here we present one- to four-fold, with some deeper, coverage of the genome sequences of over seventy isolates of the domesticated baker's yeast, _Saccharomyces cerevisiae_, and its closest relative, the wild _S. paradoxus_, which has never been associated with human activity. These were collected from numerous geographic locations and sources (including wild, clinical, baking, wine, laboratory and food spoilage). These sequences provide an unprecedented view of the population structure, natural (and artificial) selection and genome evolution in these species. Variation in gene content, SNPs, indels, copy numbers and transposable elements provide insights into the evolution of different lineages. Phenotypic variation broadly correlates with global genome-wide phylogenetic relationships however there is no correlation with source. _S. paradoxus_ populations are well delineated along geographic boundaries while the variation among worldwide _S. cerevisiae_ isolates show less differentiation and is comparable to a single _S. paradoxus_ population. Rather than one or two domestication events leading to the extant baker's yeasts, the population structure of _S. cerevisiae_ shows a few well defined geographically isolated lineages and many different mosaics of these lineages, supporting the notion that human influence provided the opportunity for outbreeding and production of new combinations of pre-existing variation