scholarly journals From baker's yeast to genetically modified budding yeasts: the scientific evolution of bioethanol industry from sugarcane

2020 ◽  
Author(s):  
Sandra Regina Ceccato-Antonini ◽  
Elizabete Aparecida Covre
Keyword(s):  
Selection Criteria ◽  
Fermentation Process ◽  
Selective Pressure ◽  
Genetically Modified ◽  
Product Yield ◽  
Fuel Ethanol ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Genomic Information ◽  
Yeast Strains

Abstract The peculiarities of Brazilian fuel ethanol fermentation allow the entry of native yeasts that may dominate over the starter strains of Saccharomyces cerevisiae and persist throughout the sugarcane harvest. The switch from the use of baker's yeast as starter to selected budding yeasts obtained by a selective pressure strategy was followed by a wealth of genomic information that enabled the understanding of the superiority of selected yeast strains. This review describes how the process of yeast selection evolved in the sugarcane-based bioethanol industry, the selection criteria, and recent advances in genomics that could advance the fermentation process. The prospective use of genetically modified yeast strains, specially designed for increased robustness and product yield, with special emphasis to those obtained by the CRISPR-Cas9 genome-editing approach, is discussed as a possible solution to confer higher performance and stability to the fermentation process for fuel ethanol production.

scholarly journals QUANTIFICAÇÃO DO METABOLISMO RESPIROFERMENTATIVO DE LEVEDURAS DE CERVEJA, VINHO E PÃO POR MÉTODO ESTEQUIOMÉTRICO

2021 ◽  
Vol 36 (1) ◽  
pp. 10-16
Author(s):  
Ricardo Figueira ◽  
Lucas Felipe Dos Ouros ◽  
Isabela Penteriche De Oliveira ◽  
Thalia Lee Lopes De Andrade ◽  
Waldemar Gastoni Venturini Filho
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Room Temperature ◽  
Fermentation Process ◽  
Red Wine ◽  
Wine Yeast ◽  
White Wine ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Fermentative Metabolism ◽  
Yeast Strains

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. [email protected]; [email protected]; [email protected]; [email protected]; [email protected]   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.

scholarly journals Importance of Proteasome Gene Expression during Model Dough Fermentation after Preservation of Baker's Yeast Cells by Freezing

2018 ◽  
Vol 84 (12) ◽  
Author(s):  
Daisuke Watanabe ◽  
Hiroshi Sekiguchi ◽  
Yukiko Sugimoto ◽  
Atsushi Nagasawa ◽  
Naotaka Kida ◽  
...  
Keyword(s):  
Cell Viability ◽  
Transcriptional Activator ◽  
Proteasomal Degradation ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Fermentation Performance ◽  
Content Type ◽  
Freeze Thaw ◽  
Ubiquitinated Proteins ◽  
Yeast Strains

ABSTRACT Freeze-thaw stress causes various types of cellular damage, survival and/or proliferation defects, and metabolic alterations. However, the mechanisms underlying how cells cope with freeze-thaw stress are poorly understood. Here, model dough fermentations using two baker's yeast strains, 45 and YF, of Saccharomyces cerevisiae were compared after 2 weeks of cell preservation in a refrigerator or freezer. YF exhibited slow fermentation after exposure to freeze-thaw stress due to low cell viability. A DNA microarray analysis of the YF cells during fermentation revealed that the genes involved in oxidative phosphorylation were relatively strongly expressed, suggesting a decrease in the glycolytic capacity. Furthermore, we found that mRNA levels of the genes that encode the components of the proteasome complex were commonly low, and ubiquitinated proteins were accumulated by freeze-thaw stress in the YF strain. In the cells with a laboratory strain background, treatment with the proteasome inhibitor MG132 or the deletion of each transcriptional activator gene for the proteasome genes ( RPN4 , PDR1 , or PDR3 ) led to marked impairment of model dough fermentation using the frozen cells. Based on these data, proteasomal degradation of freeze-thaw-damaged proteins may guarantee high cell viability and fermentation performance. We also found that the freeze-thaw stress-sensitive YF strain was heterozygous at the PDR3 locus, and one of the alleles (A148T/A229V/H336R/L541P) was shown to possess a dominant negative phenotype of slow fermentation. Removal of such responsible mutations could improve the freeze-thaw stress tolerance and the fermentation performance of baker's yeast strains, as well as other industrial S. cerevisiae strains. IMPORTANCE The development of freezing technology has enabled the long-term preservation and long-distance transport of foods and other agricultural products. Fresh yeast, however, is usually not frozen because the fermentation performance and/or the viability of individual cells is severely affected after thawing. Here, we demonstrate that proteasomal degradation of ubiquitinated proteins is an essential process in the freeze-thaw stress responses of S. cerevisiae . Upstream transcriptional activator genes for the proteasome components are responsible for the fermentation performance after freezing preservation. Thus, this study provides a potential linkage between freeze-thaw stress inputs and the transcriptional regulatory network that might be functionally conserved in higher eukaryotes. Elucidation of the molecular targets of freeze-thaw stress will contribute to advances in cryobiology, such as freezing preservation of human cells, tissues, and embryos for medical purposes and breeding of industrial microorganisms and agricultural crops that adapt well to low temperatures.

Comparison of melibiose utilizing baker’s yeast strains produced by genetic engineering and classical breeding

1999 ◽  
Vol 28 (2) ◽  
pp. 148-152 ◽  
Author(s):  
S. F. Vincent ◽  
P. J. L. Bell ◽  
P. Bissinger ◽  
K. M. H. Nevalainen
Keyword(s):  
Genetic Engineering ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Yeast Strains

scholarly journals Bioethanol Production from Enzymatic Hydrolyzates of Pretreated Flaxseed Meals by Baker’s Yeast

2021 ◽  
Author(s):  
SAHELI GHOSAL ◽  
JAYATI BHOWAL
Keyword(s):  
Enzymatic Hydrolysis ◽  
Fermentation Process ◽  
Reducing Sugars ◽  
Reducing Sugar ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Bioethanol Production ◽  
Dilute Acid ◽  
Cellulose Conversion ◽  
Flaxseed Meal

Abstract The present study investigated the usefulness of flaxseed meals as a novel feedstock for the production of bioethanol. The proximate composition of the flaxseed meal was carried out before the pretreatment of the flaxseed meal. In this study, flaxseed meal was pretreated with dilute acid, alkali, and aqueous for disruption of lignocellulosic compounds. The acid pretreated flaxseed meal was used for enzymatic hydrolysis by different enzymes (cellulase, α-amylase, and cellulase combined with α-amylase) for better release of reducing sugar. The cellulose conversion to reducing sugar was significantly higher for acid pretreated flaxseed meals. After enzymatic hydrolysis with cellulase, cellulose conversions to reducing sugars were found to be significantly higher than those of α-amylase and cellulase combined with α-amylase. The bioethanol production was also investigated. The fermentation process was carried out by using baker’s yeast (Saccharomyces cerevisiae) with the acid pretreated flaxseed meal enzymatic hydrolyzate. Maximum ethanol production (0.11 g/l) was achieved from the fermented medium obtained from the acid pretreated flaxseed meal followed by enzymatic hydrolysis by using cellulase enzyme. The structural analysis of bioethanol was also investigated by FTIR.

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