scholarly journals Bioethanol production from intermediate products of sugar beet processing with different types of Saccharomyces cerevisiae

2009 ◽  
Vol 15 (1) ◽  
pp. 13-16 ◽  
Author(s):  
Jovana Rankovic ◽  
Jelena Dodic ◽  
Sinisa Dodic ◽  
Stevan Popov
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fossil Fuels ◽  
Specific Growth ◽  
Culture Media ◽  
Ethanol Yield ◽  
Sugar Utilization ◽  
Yeast Strains ◽  
Different Types ◽  
Thick Juice ◽  
Different Strains

The use of biofuels as an alternative to fossil fuels has expanded in the last few decades. The aim of this study was to examine the application of different strains and forms of Saccharomyces cerevisiae for raw, thin and thick juice fermentation in order to produce bioethanol. According to the obtained results the strain applied in the form of pressed blocks with 70 % w/w moisture, attained higher value of the specific growth rate and lower value of ethanol yield in comparison with strains applied in dried form. In all culture media attained efficiency of sugar utilization was at least from 98-99 % w/w. Maximum productivity was achieved around 30th hour of fermentation and amounted ?1.8 g l?? h?? for all applied yeast strains. Therefore, optimal duration of the process in technical and economic terms should be considered.

Ethanol Production from Different Substrates by a Flocculent Saccharomyces cerevisiae Strain

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
José Duarte ◽  
Vera Lourenço ◽  
Belina Ribeiro ◽  
Maria Céu Saagua ◽  
Joana Pereira ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Yeast Strain ◽  
Fossil Fuels ◽  
Ethanol Yield ◽  
Corn Fiber ◽  
Production Costs ◽  
Raw Material ◽  
Continuous Reactor ◽  
Different Strains

During the last years there has been an increasing interest in using ethanol as a substitute for fossil fuels. The bioethanol used today is mainly produced from sugar cane and cereals, but reducing the production costs of ethanol is still crucial for a viable economic process. Cellulose from vegetable biomass will be the next cheap raw material for second generation fuel ethanol production and agricultural by-products with a low commercial value, as corn stover, corn fiber and cane bagasses would become an attractive feedstock for bioethanol production.In this study, different strains of Saccharomyces cerevisiae have been screened for the ability of bioethanol production. Yeasts were grown in a synthetic liquid medium containing sucrose in batch regime and the growth rates, ethanol and biomass productions were determined as well as their growth ability in cane molasses.The results indicate that a flocculent yeast, isolated in our lab and designated by strain F, was the most promising yeast strain among those tested for continuous ethanol production. This strain was isolated from corn hydrolysates, obtained from a Portuguese distillery facility (DVT, Torres Novas, Portugal) showing highest growth rate (0.49h-1), highest ethanol yield (0.35g/g) and high flocculation capacity.The study on ethanol production in continuous reactor process with the selected yeast strain (strain F) was made on sucrose and cane molasses at different dilution rates (0.05-0.42 h-1). A steady flocculating yeast fluidized bed reactor system was established allowing the functioning of the reactor for 1000 h. Data shows that when the dilution rate rose to 0.42h-1, the highest productivity (20g/Lh) was obtained attaining an ethanol concentration in the reactor of 47g/L for sucrose and molasses media.

Role of cations in the flocculation of Saccharomyces cerevisiae and discrimination of the corresponding proteins

1991 ◽  
Vol 37 (5) ◽  
pp. 397-403 ◽  
Author(s):  
Hiroshi Kuriyama ◽  
Itaru Umeda ◽  
Harumi Kobayashi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Surface ◽  
Inhibitory Effect ◽  
Surface Proteins ◽  
Promoting Effect ◽  
Yeast Strains ◽  
Yeast Flocculation ◽  
Different Types ◽  
Anionic Groups

Asexual yeast flocculation was studied using strong flocculents of Saccharomyces cerevisiae. The inhibitory effect of cations on flocculation is considered to be caused by competition between those cations and Ca2+ at the binding site of the Ca2+-requiring protein that is involved in flocculation. Inhibition of flocculation by various cations occurred in the following order: La3+, Sr2+, Ba2+, Mn2+, Al3+, and Na+. Cations such as Mg2+, Co2+, and K+ promoted flocculation. This promoting effect may be based on the reduction of electrostatic repulsive force between cells caused by binding of these cations anionic groups present on the cell surface. In flocculation induced by these cations, trace amounts of Ca2+ excreted on the cell surface may activate the corresponding protein. The ratio of Sr2+/Ca2+ below which cells flocculated varied among strains: for strains having the FLO5 gene, it was 400 to 500; for strains having the FLO1 gene, about 150; and for two alcohol yeast strains, 40 to 50. This suggests that there are several different types of cell surface proteins involved in flocculation in different yeast strains. Key words: yeast, flocculation, protein, cation, calcium.

scholarly journals Recombinant Diploid Saccharomyces cerevisiae Strain Development for Rapid Glucose and Xylose Co-Fermentation

Fermentation ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 59 ◽  
Author(s):  
Tingting Liu ◽  
Shuangcheng Huang ◽  
Anli Geng
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Xylose Isomerase ◽  
Cost Effective ◽  
Xylose Utilization ◽  
Yeast Strains ◽  
Multiple Copies ◽  
Biomass Sugars ◽  
Sugar Conversion

Cost-effective production of cellulosic ethanol requires robust microorganisms for rapid co-fermentation of glucose and xylose. This study aims to develop a recombinant diploid xylose-fermenting Saccharomyces cerevisiae strain for efficient conversion of lignocellulosic biomass sugars to ethanol. Episomal plasmids harboring codon-optimized Piromyces sp. E2 xylose isomerase (PirXylA) and Orpinomyces sp. ukk1 xylose (OrpXylA) genes were constructed and transformed into S. cerevisiae. The strain harboring plasmids with tandem PirXylA was favorable for xylose utilization when xylose was used as the sole carbon source, while the strain harboring plasmids with tandem OrpXylA was beneficial for glucose and xylose cofermentation. PirXylA and OrpXylA genes were also individually integrated into the genome of yeast strains in multiple copies. Such integration was beneficial for xylose alcoholic fermentation. The respiration-deficient strain carrying episomal or integrated OrpXylA genes exhibited the best performance for glucose and xylose co-fermentation. This was partly attributed to the high expression levels and activities of xylose isomerase. Mating a respiration-efficient strain carrying the integrated PirXylA gene with a respiration-deficient strain harboring integrated OrpXylA generated a diploid recombinant xylose-fermenting yeast strain STXQ with enhanced cell growth and xylose fermentation. Co-fermentation of 162 g L−1 glucose and 95 g L−1 xylose generated 120.6 g L−1 ethanol in 23 h, with sugar conversion higher than 99%, ethanol yield of 0.47 g g−1, and ethanol productivity of 5.26 g L−1·h−1.

scholarly journals Redox Interactions between Saccharomyces cerevisiae and Saccharomyces uvarum in Mixed Culture under Enological Conditions

2005 ◽  
Vol 71 (1) ◽  
pp. 255-260 ◽  
Author(s):  
Naoufel Cheraiti ◽  
St�phane Guezenec ◽  
Jean-Michel Salmon
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mixed Culture ◽  
Wine Yeast ◽  
Redox Status ◽  
Product Formation ◽  
Hybrid Strain ◽  
Saccharomyces Uvarum ◽  
Yeast Strains ◽  
Different Strains ◽  
Different Cultures

ABSTRACT Wine yeast starters that contain a mixture of different industrial yeasts with various properties may soon be introduced to the market. The mechanisms underlying the interactions between the different strains in the starter during alcoholic fermentation have never been investigated. We identified and investigated some of these interactions in a mixed culture containing two yeast strains grown under enological conditions. The inoculum contained the same amount (each) of a strain of Saccharomyces cerevisiae and a natural hybrid strain of S. cerevisiae and Saccharomyces uvarum. We identified interactions that affected biomass, by-product formation, and fermentation kinetics, and compared the redox ratios of monocultures of each strain with that of the mixed culture. The redox status of the mixed culture differed from that of the two monocultures, showing that the interactions between the yeast strains involved the diffusion of metabolite(s) within the mixed culture. Since acetaldehyde is a potential effector of fermentation, we investigated the kinetics of acetaldehyde production by the different cultures. The S. cerevisiae-S. uvarum hybrid strain produced large amounts of acetaldehyde for which the S. cerevisiae strain acted as a receiving strain in the mixed culture. Since yeast response to acetaldehyde involves the same mechanisms that participate in the response to other forms of stress, the acetaldehyde exchange between the two strains could play an important role in inhibiting some yeast strains and allowing the growth of others. Such interactions could be of particular importance in understanding the ecology of the colonization of complex fermentation media by S. cerevisiae.

Rearrangements of highly polymorphic regions near telomeres of Saccharomyces cerevisiae

1984 ◽  
Vol 4 (11) ◽  
pp. 2509-2517
Author(s):  
H Horowitz ◽  
P Thorburn ◽  
J E Haber
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Homologous Sequence ◽  
Tetrad Analysis ◽  
Homologous Chromosomes ◽  
Restriction Fragments ◽  
Yeast Strains ◽  
Number Of Genes ◽  
Restriction Endonuclease Fragment ◽  
Different Strains ◽  
Gene Conversions

We have examined the mitotic and meiotic properties of telomeric regions in various laboratory strains of yeast. Using a sequence (Y probe) derived from a cloned yeast telomere (J. Szostak and E. Blackburn, Cell 29:245-255, 1982), we found that various strains of Saccharomyces cerevisiae show extensive polymorphisms of restriction endonuclease fragment length. Some of the variation in the lengths of telomeric fragments appears to be under the control of a small number of genes. When DNA from various strains was digested with endonuclease KpnI, nearly all of the fragments homologous to the Y probe were found to be of different size. The pattern of fragments in different strains was extremely variable, with a greater degree of polymorphism than that observed for fragments containing the mobile TY1 element. Tetrad analysis of haploid meiotic segregants from diploids heterozygous for many different Y-homologous KpnI fragments revealed that most of them exhibited Mendelian (2:0) segregation. However, only a small proportion of these fragments displayed the obligate 2:2 parental segregation expected of simple allelic variants at the same chromosome end. From the segregations of these fragments, we concluded that some yeast telomeres lack a Y-homologous sequence and that the chromosome arms containing a Y-homologous sequence are different among various yeast strains. Regions near yeast telomeres frequently undergo rearrangement. Among eight tetrads from three different diploids, we have found three novel Y-homologous restriction fragments that appear to have arisen during meiosis. In all three cases, the appearance of a new fragment was accompanied by the loss of another band. In one of these cases, the rearrangement leading to a novel fragment arose in an isogenic diploid, in which both homologous chromosomes should have been identical. Among these same tetrads we also found examples of apparent mitotic gene conversions and mitotic recombination involving telemetric regions.

scholarly journals Improvement of L-Arabinose Fermentation by Modifying the Metabolic Pathway and Transport inSaccharomyces cerevisiae

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Chengqiang Wang ◽  
Yu Shen ◽  
Yanyan Zhang ◽  
Fan Suo ◽  
Jin Hou ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Recombinant Strain ◽  
Consumption Rate ◽  
Specific Growth ◽  
Ethanol Yield ◽  
Maximum Specific Growth Rate ◽  
Dry Cell Weight ◽  
Utilization Pathway ◽  
Dry Cell ◽  
Arabinose Fermentation

The L-arabinose utilization pathway was established inSaccharomyces cerevisiae, by expressing the codon-optimizedaraA,araB, andaraDgenes ofLactobacillus plantarum. After overexpressing theTAL1,TKL1,RPE1,RKI1, andGAL2genes and adaptive evolution, the L-arabinose utilization of the recombinant strain became efficient. The resulting strain displayed a maximum specific growth rate of 0.075 h−1, a maximum specific L-arabinose consumption rate of 0.61 g h−1 g−1dry cell weight, and a promising ethanol yield of 0.43 g g−1from L-arabinose fermentation.

Isolation of Saccharomyces cerevisiae YDJ05 from the Spontaneous Fermentation Pear Wine and Study of the Yeast Growth Dynamics during the Association Fermentation

2010 ◽  
Vol 156-157 ◽  
pp. 266-271
Author(s):  
Da Wei Zhang ◽  
Wenbin Dong ◽  
Lei Jin ◽  
Jie Zhang ◽  
Yuan Chang Jin
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Growth Dynamics ◽  
Yeast Growth ◽  
Yeast Saccharomyces Cerevisiae ◽  
Spontaneous Fermentation ◽  
Potential Source ◽  
Yeast Strains ◽  
Better Than

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.

scholarly journals Assessment of the Effect of Nitrogen Concentration on Fermentation and Selection of a Highly Competitive Saccharomyces cerevisiae Strain for Efficient Ethanol Production

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2614
Author(s):  
Barahona ◽  
Martín-Gil ◽  
Martín-Ramos ◽  
Pérez ◽  
Barriga
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Ethanol Yield ◽  
Nitrogen Concentration ◽  
Glucose Consumption ◽  
Cellular Growth ◽  
Yeast Strains ◽  
Two Factors ◽  
Pilot Plant Scale ◽  
Reducing Costs

: The optimum nitrogen concentration for media supplementation and strain dominance are aspects of key importance to the industrial production of ethanol with a view to reducing costs and increasing yields. In this work, these two factors were investigated for four ethanologenic Saccharomyces cerevisiae strains (CLQCA-INT-001, CLQCA-INT-005, CLQCA-10-099, and UCLM 325), selected from the screening of 150 isolates, mostly from Ecuadorian yeast biodiversity. The effect of nitrogen concentration was assessed in terms of cellular growth, glucose consumption and ethanol production, and the yeast strains’ dominance was evaluated in continuous co-fermentation with cellular recycling by mitochondrial DNA analyses. Among the four selected yeast strains under study, CLQCA-INT-005 presented the highest glucose consumption at a nitrogen supplement concentration as low as 0.4 g·L−1, attaining an ethanol yield of up to 96.72% in 24 h. The same yeast strain was found to be highly competitive, showing a dominance of 80% after four cycles of fermentation in co-culture. Thus, CLQCA-INT-005 may be deemed as a very promising candidate to be used both at pilot-plant scale and at industrial scale cellulosic ethanol production.

scholarly journals Effective Hydrogenation of 3-(2”-furyl)- and 3-(2”-thienyl)-1-(2’-hydroxyphenyl)-prop-2-en-1-one in Selected Yeast Cultures

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3185 ◽  
Author(s):  
Łużny ◽  
Krzywda ◽  
Kozłowska ◽  
Kostrzewa-Susłow ◽  
Janeczko
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Double Bond ◽  
Yarrowia Lipolytica ◽  
Sulfur Atom ◽  
Efficient Production ◽  
Chalcone Derivatives ◽  
Yeast Cultures ◽  
Yeast Strains ◽  
Different Strains

Biotransformations were performed on eight selected yeast strains, all of which were able to selectively hydrogenate the chalcone derivatives 3-(2”-furyl)- (1) and 3-(2”-thienyl)-1-(2’-hydroxyphenyl)-prop-2-en-1-one (3) into 3-(2”-furyl)- (2) and 3-(2”-thienyl)-1-(2’-hydroxyphenyl)-propan-1-one (4) respectively. The highest efficiency of hydrogenation of the double bond in the substrate 1 was observed in the cultures of Saccharomyces cerevisiae KCh 464 and Yarrowia lipolytica KCh 71 strains. The substrate was converted into the product with > 99% conversion just in six hours after biotransformation started. The compound containing the sulfur atom in its structure was most effectively transformed by the Yarrowia lipolytica KCh 71 culture strain (conversion > 99%, obtained after three hours of substrate incubation). Also, we observed that, different strains of tested yeasts are able to carry out the bioreduction of the used substrate with different yields, depending on the presence of induced and constitutive ene reductases in their cells. The biggest advantage of this process is the efficient production of one product, practically without the formation of side products.

scholarly journals Continuous ethanol production from sugar beet thick juice by Saccharomyces cerevisiae immobilized onto sugar beet pulp

2013 ◽  
pp. 313-321 ◽  
Author(s):  
Vesna Vucurovic ◽  
Radojka Razmovski ◽  
Uros Miljic ◽  
Vladimir Puskas
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sugar Beet ◽  
Ethanol Production ◽  
Dilution Rate ◽  
Immobilized Cells ◽  
Ethanol Yield ◽  
Low Cost ◽  
Sugar Beet Pulp ◽  
Beet Pulp ◽  
Thick Juice

The immobilization of Saccharomyces cerevisiae onto sugar beet pulp (SBP) by natural adhesion is an efficient and low-cost method for retaining high biocatalyst density in the ethanol fermentation system. In the present study, cells of S. cerevisiae 163, were immobilized by natural adhesion onto SBP. The retention of immobilized cells attained the level of about 1.7?1011 cells/gram of dry SBP. Continuous ethanol production from sugar beet thick juice (TJ) was performed in a cylinder glass bioreactor at a temperature of 30?C and pH 5 during a 27-day period. The stability of the fermentation process at dilution rate (D) of 0.025 h-1 and 0.05 h-1 was evaluated. The yeast-SBP system was shown to be stable for over a 15-day period at the dilution rate of 0.025 h-1, while the dilution rate of 0.05 h-1 was found to be unsuitable due to the intensive yeast leaching from the support. At D of 0.025 h-1 the maximum sugar utilization (Su), ethanol concentration (P), volumetric ethanol productivity (Qp), ethanol yield (Yp/s) and fermentation efficiency were 97.1%, 54.7 g/l, 2.3 g/lh, 0.498 g/g and 97.6%, respectively.

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