scholarly journals Rational Selection of Mixed Yeasts Starters for Agave Must Fermentation

2021 ◽  
Vol 5 ◽  
Author(s):  
Claudia Patricia Larralde-Corona ◽  
Francisco Javier De la Torre-González ◽  
Pedro Alberto Vázquez-Landaverde ◽  
Dittmar Hahn ◽  
José Alberto Narváez-Zapata
Keyword(s):  
Synthetic Medium ◽  
Isoamyl Acetate ◽  
High Survival ◽  
Rational Selection ◽  
Primary Metabolite ◽  
Ethyl Hexanoate ◽  
High Productivity ◽  
Mixed Inoculum ◽  
High Production ◽  
Selection Of

Tequila and mezcal are both traditional Mexican liquors that are produced from cooked Agave spp. must fermentation and usually rely on spontaneous or pure Saccharomyces cerevisiae strain inoculation. In order to contribute to the rational selection of yeast starters for tequila and mezcal productions, we tested a collection of 25 yeasts originally isolated from mezcal musts, spanning 10 different yeast species. These strains were first characterized in a semi synthetic medium (labeled as M2, having 90 g/L fructose and 10 g/L glucose of initial hexoses) at 48 h of culture, observing a differential pattern in the consumption of sugars and productivity. Selected Saccharomyces strains left around 10 g/L of fructose and showed higher fermentation performance. However, some non-Saccharomyces strains, specifically from Torulospora (Td), Kluyveromyces (Km), and Zygosaccharomyces (Zb) genera, consumed almost all the sugar (i.e., Km1Y9 with <5 g/L) and had a high productivity of ethanol. In general, all Saccharomyces strains presented a high production of ethyl-butyrate, ethyl-decanoate, and ethyl-hexanoate with peaks of 10, 38, and 3 μg/L, respectively. In addition, some Kluyveromyces and Torulospora strains showed a high production of phenyl ethyl acetate (i.e., Km1D5 with up to 1400 μg/L); isoamyl acetate (i.e., Km1D5 and Td1AN2 with more than 300 μg/L), and hexyl acetate (i.e., Td1AN2 with 0.3 μg/L). Representative strains of the most productive genera (Saccharomyces, Torulospora, and Kluyveromyces) were selected to evaluate their fermentative performance and survival in a mixed culture on a medium based on Agave tequilana must, and their population kinetics was characterized using specific fluorescent in situ hybridization (FISH) probes in a qualitative and semi-quantitative analysis during fermentation. We observed that the mixture ratios of 0.1:1:1 or 1:1:1 (Saccharomyces:Kluyveromyces:Torulospora), maintained good fermentation productivities, with alcohol yields above 0.45 g/g, and allowed a high survival rate of the non-Saccharomyces strains during the fermentation process. Finally, mixed inoculum fermentations on A. tequilana must medium, including different Saccharomyces strains and the finally selected Torulospora and Kluyveromyces strains, showed the best production parameters in terms of ethanol, carbon dioxide, glycerol, and acetic acid values, as well as improved volatile metabolite profiles as compared to the pure cultures. All these data were used to propose a methodology of selection of strains to be used as a pure or mixed starter for tequila and mezcal fermentations, with high primary metabolite productivity and desired aromatic profile.

scholarly journals Mezcal as a Novel Source of Mixed Yeasts Inocula for Wine Fermentation

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1296
Author(s):  
Francisco Javier De la Torre-González ◽  
José Alberto Narváez-Zapata ◽  
Patricia Taillandier ◽  
Claudia Patricia Larralde-Corona
Keyword(s):  
Synthetic Medium ◽  
Grape Juice ◽  
Isoamyl Alcohol ◽  
Zygosaccharomyces Bailii ◽  
Commercial Strain ◽  
Mixed Inoculum ◽  
Wine Strain ◽  
The Individual ◽  
Final Selection ◽  
Selection Of

Mezcal yeasts were evaluated for their potential as grape-juice fermenters, characterizing their fermentation performance, both in terms of primary and volatile metabolites. Experiments were first carried-out in a semi-synthetic medium and then on grape juice, and population dynamics of the chosen mixed inoculum was assessed in grape juice. Accordingly, we initially tested 24 mezcal yeasts belonging to ten different species, and chose those that were more productive and stress tolerant for the mixed (dual) inoculum, having a final selection of three Saccharomyces cerevisiae strains (plus Fermichamp, a commercial wine strain) and three non-Saccharomyces strains, belonging to Kluyveromyces marxianus, Torulaspora delbrueckii, and Zygosaccharomyces bailii species. For the combination S. cerevisiae/T. delbrueckii (Sc/Td) mixed inoculum, we observed increasing isoamyl alcohol and phenyl ethyl acetate concentrations, as compared with the use of individual Saccharomyces strains, which resulted in a fruitier aroma profile. Alcohol final concentration was in average lower for the Sc/Td inoculum (fermentation power, FP, 13.6) as compared with the individual mezcal Saccharomyces strains (FP 14.3), and it was the highest when Td was co-cultured with the commercial strain (FP 14.6). Overall, our results show the feasibility of using yeasts isolated from mezcal as a novel source of inoculum for wine-type fermentation.

scholarly journals The use of cement concrete pavements for roads, depending on climatic conditions

2019 ◽  
Vol 13 (3) ◽  
pp. 235-240
Author(s):  
Iryna Solonenko
Keyword(s):  
European Union ◽  
Statistical Models ◽  
Road Network ◽  
The European Union ◽  
Rational Selection ◽  
Cement Concrete ◽  
The Road ◽  
Road Pavement ◽  
Operational Characteristics ◽  
Selection Of

The development of road network infrastructure is an important component of the economic development of the European Union. Updating of the road network contributes to the integration of the economies of countries into a coherent whole. The road network provides the free movement of citizens, the movement of goods and the effective implementation of various services. The increase in the length of the road network leads to an increase in the financial and material costs necessary to ensure its maintenance and repair. One of the ways to reduce costs is by strengthening the physic-mechanical and operational characteristics of the pavement due to the widespread use of cement concrete. The quality of the pavement of cement concrete depends largely on the rational selection of its composition. This allows a significant increase in the durability of road pavement. The purpose of the research was: the development of recommendations for the rational selection of the composition of the road pavement material of cement concrete, aimed at upgrading longevity, and taking into account its frost resistance grade. According to the goal, the following tasks were developed: the analyses of the climatic zones in which the road network of the European Union is located; the development of a research plan, a selection of the response function and influence factors; the study of physico-mechanical and operational characteristics of the researched material of road pavement; on the basis of the obtained data, the calculation of the complex of experimental-statistical models, which describe the physico-mechanical and operational characteristics of the road pavement material; on the basis of experimental statistical models, a method was proposed for selecting the rational compositions of the cement concrete pavement road material depending on the conditions of its application. The results presented in the article can be used in engineering and scientific practice for the selection of road pavement from cement concrete for highways.

scholarly journals SELECTION OF HERBICIDES TARGETING THE USE IN CROP SYSTEMS CULTIVATED WITH SHOWY CROTALARIA

2015 ◽  
Vol 33 (3) ◽  
pp. 521-534 ◽  
Author(s):  
G. B. P BRAZ ◽  
R. S OLIVEIRA JR ◽  
J. CONSTANTIN ◽  
H. K. TAKANO ◽  
C. A. CHASE ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Chemical Control ◽  
Clayey Soil ◽  
Chlorimuron Ethyl ◽  
High Production ◽  
Low Levels ◽  
Postemergence Herbicides ◽  
Potential Use ◽  
Selection Of

ABSTRACT The increase in the area planted with Crotalaria spectabilishas occurred by several factors, highlighting the potential to reduce the nematodes, nitrogen fixation and the high production of biomass. By becoming a species sown as a crop, it is necessary to control the weeds that coexist with showy crotalaria. This change in the use of this crop creates the possibility of this specie becoming a weed. The aim of this study was to assess the potential use of herbicides applied in preemergence and postemergence of C.spectabilisfor different purposes (control of volunteer and selectivity plants). Three experiments were installed in a greenhouse (two with herbicides applied in preemergence - in soils with distinct textural categories; and one experiment with herbicides applied in postemergence). The results of the experiments with herbicides applied in preemergence showed that: amicarbazone, atrazine, diuron, metribuzin, prometryn, fomesafen and sulfentrazone showed effectiveness for control of C.spectabilis in clayey soil. Besides these, flumioxazin and isoxaflutole also showed potential to be used in the control of showy crotalaria in soils with loam texture. In relation to the postemergence herbicides, atrazine, diuron, prometryn, flumioxazin, fomesafen, lactofen, saflufenacil, amonio-glufosinate and glyphosate can be used aiming the chemical control of C.spectabilis. Herbicides chlorimuron-ethyl, diclosulan, imazethapyr, pyrithiobac-sodium, trifloxysulfuron-sodium, clomazone, pendimethalin, S-metolachlor and trifluralin applied in preemergence, and imazethapyr, pyrithiobac-sodium, flumiclorac, bentazon and clethodim applied in postemergence caused low levels of injury to C.spectabilis plants, making necessary the development of new searches to ensure the selectivity of these products.

scholarly journals ECOLOGICAL-GEOGRAPHIC APPROACHES TO THE STUDY OF GENETIC DIVERSITY OF BARLEY AND OAT FROM THE VIR COLLECTION

2020 ◽  
Author(s):  
Igor Loskutov ◽  
Lubov Novikova ◽  
Olga Kovaleva ◽  
Nadezhda Ivanova ◽  
Elena Blinova ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Growing Season ◽  
Regression Coefficients ◽  
Cultivation Conditions ◽  
High Productivity ◽  
Sum Of Effective Temperatures ◽  
Economically Valuable Traits ◽  
Effective Temperatures ◽  
The Stability ◽  
Selection Of

Under conditions of climate change, the assessment of the stability of genotypes is of particular importance. To conduct directed selection of genotypes with a narrow or broad reaction rate, it is necessary to assess their stability already in the early stages of breeding. The aim of the study was to study the stability of breeding significant traits of oat and barley samples in contrasting ecological and geographical conditions. 25 oat samples and 25 barley samples were studied over 3 years under contrasting conditions in St. Petersburg and the Tambov region. Varieties are characterized by average values of economically valuable traits and genotype regression coefficients on the influence of the bi environment according to Eberhart and Russell. The most sensitive to a change in the ecological and geographical situation were the durations of the germination-heading, germination-harvest periods and grain yield. These characters varied to a greater extent depending on the cultivation conditions than on the genotype. According to regression coefficients for environmental conditions, significant differences in genotypes were only in yield. Contrasting groups of varieties were distinguished by regression coefficients on environmental conditions, genotypes with high productivity. The durations of germination-heading, germination-harvest, the plant height reacted to the change in the environment the same in different varieties. The duration of the growing season was determined by the sum of effective temperatures above 15C. The reduction of the growing season in both crops was 3 days with an increase in the sum of effective temperatures above 15C by 100C.

scholarly journals Rational selection of treatment methods in recurrent clubfoot

2021 ◽  
pp. 64-71
Author(s):  
G. V. Divovich
Keyword(s):  
Surgical Treatment ◽  
Bone Growth ◽  
Soft Tissues ◽  
Primary Treatment ◽  
Ponseti Method ◽  
Growth Potential ◽  
Idiopathic Clubfoot ◽  
Rational Selection ◽  
Congenital Clubfoot ◽  
Selection Of

Objective. Based on an analytical assessment of the results of surgical treatment of children with equinovarus foot deformity of various origins (idiopathic clubfoot, syndromic clubfoot), to determine a way of rational selection of surgical techniquesin each specifc case.Materials and methods. The results of the treatment of 78 children with congenital idiopathic clubfoot over the period 2010–2018 were assessed in comparison with the results of the treatment of 41 children with recurrent congenital clubfoot, whose primary treatment had been carried out before 2010. We have gained the experience in treating 30 children with severe clubfoot syndrome (meningomyelocele, CNS lesions, chromosomal diseases and others).Results. In the treatment of congenital clubfoot with the Ponseti method, recurrences occur in 21.79 % of the cases, and in the traditional treatment — in 57.74 %. The Ponseti surgical treatment of recurrences consists in performing release operations on the tendon-ligament apparatus from mini-accesses. Cases of rigid, long-standing deformities require extensive releases on soft tissues, as well as resection and arthrodesis interventions on the joints of the foot. The treatment of clubfoot syndrome requires “surgically aggressive” methods of correction in early childhood.Conclusion. In the idiopathic variants of clubfoot and its relapses, it is possible to correct the vicious position of the feet by minimally invasive operations with minimal damage to the tissues of the circumflex joints and without damage to the flexor tendons and their sheaths in the medial ankle area. Long-standing recurrent rigid variants, as well as syndromic clubfoot, presuppose the performance of extensive releases, osteotomies and arthrodetic resections of the joints of the foot at an early age. A promising direction for clubfoot correction in the process of child development is a surgery with the use of the bone growth potential of the lower leg and foot.

Rational selection of immunodominant and preserved epitope Sm043300e from Schistosoma mansoni and design of a chimeric molecule for biotechnological purposes

2018 ◽  
Vol 93 ◽  
pp. 133-143 ◽  
Author(s):  
Cláudia de Souza ◽  
Marcelo Donizete Lopes ◽  
Flávio Martins De Oliveira ◽  
Maria Juliana Ferreira Passos ◽  
Laís Cunha Grossi Ferreira ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Rational Selection ◽  
Selection Of
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