Translational regulation and biotechnology of yeast

Various species of microorganisms participate in the fermentation of a wide variety of biological matrices, contribute functional substances to different fermented foods and give them nutritional, organoleptic and sensory profiles that define their identity or typicality. Spontaneous fermentations of plant matrices can be used to isolate strains of microorganisms suitable for producing products with new textures, flavors or aromas, or for improving the nutritional profile of foods in "targeted fermentations".

The current interest of the group is to investigate the genetic and functional biodiversity of microorganisms associated with raw materials and spontaneous food fermentations, in order to select and/or generate new strains suitable for microbiological innovation in baking and winemaking. We evaluate the technological capabilities of yeast strains and lactic acid bacteria of beneficial species, and generate new optimized and hybrid yeasts.

We recently isolated 433 yeast strains of 9 species from a variety of Spanish cereal grains, flour types and sourdoughs (PANLEV collection); we investigated the evolution of the fungal microbiome during fermentation as a function of flour types and dough density, and selected different yeast strains of safe species (GRAS) with innovative properties for baking (Chiva et al..., 2021); we also isolated and genetically identified 577 strains of lactic acid bacteria (PANBAL collection) (Celador-Lera et al., in preparation). We have obtained, for the first time, non-GMO hybrids between yeasts isolated from sourdoughs and yeasts of oenological origin, whose imposition and technological qualities in the elaboration of innovative breads and in the experimental production of white wines were evaluated in previous projects with companies. In addition, we genetically and functionally characterized several strains of lactic acid bacteria isolated from dextran-producing rye sourdoughs, from which we obtained mutants overproducing riboflavin (vitamin B2), successfully used to biofortify experimental breads (Llamas-Arriba et al., 2021; Hernández-Alcántara et al., 2022; Díaz-Ozaeta et al., 2023).

Our objective is to formulate simple and/or combined starter cultures using yeasts and lactic acid bacteria from our collections, and to formulate new ones based on the relative abundance of species present in the microbiome of a group of selected sourdoughs. The inocula will be used to ferment proximate plant matrices (ancestral cereal flours, pseudocereals and legumes), and the best ones will be used in targeted fermentations to develop new, sustainable and reproducible ranges of gluten-free and gluten-containing bakery products. To that end, we developed a public-private collaboration project (NutriPanHealth, 2022-2025) funded by MCIN/AEI /10.13039/501100011033 EU Next Generation EU/ PRTR; a TCUE project (CICER4FOOD, 2022-2023) and participated in the PANVITDEX proof-of-concept (2022-2024). Some international collaborations have been established through the European Action COST -CA10101 "Sourdomics" and MTA agreements for the transfer of strains.

Figure 1. Workflow diagram for food biotechnology projects.

Figure 2. Ropy phenotype of 22 strains of dextran-producing lactic acid bacteria isolated from rye sourdoughs (MRS medium with 5% sucrose).

On the other hand, our laboratory has specialized in the identification of the molecular factors and mechanisms that regulate translation initiation in eukaryotes, through mutations that alter the translational regulation of GCN4 in Saccharomyces cerevisiae. Recent work on this topic describes the roles of the initiation factor eIF1A and the ribosomal protein eL33 in translation initiation and in particular, in the correct recognition of AUG and translation fidelity (Martín-Marcos et al., 2017; 2022).

Image description

Group Member

Mercedes Tamame González Scientist (CSIC)
Rosa Ana Chiva Tomás Postdoctoral
Pilar Gómez Jiménez Lab Technician


Mercedes Tamame González
Laboratory 1.12

Recent publications

João Miguel Rocha,Biljana Kovacevik,Sanja Kostadinović Veličkovska,Mercedes Tamame and José António Teixeira. (2023).
Screening and Characterization of the Diversity of Food Microorganisms and Their Metabolites.
Doi: 10.3390/microorganisms11051235
Diez-Ozaeta, I., Martín Loarte, L., Mohedano, M.L., Tamame, M., Ruiz-Masó J. A., Del Solar, G., Dueñas, M.T., López, P. (2023).
WA methodology for the selection and characterization of riboflavin-overproducing Weissella cibaria strains after treatment with roseoflavin.
Frontiers in Microbiology
Doi: 10.3389/fmicb.2023.1154130
Annel M. Hernández-Alcántara, Rosana Chiva, María Luz Mohedano, Pasquale Russo, José Ángel Ruiz-Masó, Gloria del Solar, Giuseppe Spano, Mercedes Tamame and Paloma López. (2022).
Weissella cibaria riboflavin-overproducing and dextran-producing strains useful for the development of functional bread.
Frontiers in Nutrition
Doi: 10.3389/fnut.2022.978831
Martín-Marcos P, Gil-Hernández Á, Tamame M. (2022).
Wide mutational analysis to ascertain the functional roles of eL33 in ribosome biogenesis and translation initiation.
Current Genetics
Doi: 10.1007/s00294-022-01251-1
Llamas-Arriba, M.G.; Hernández-Alcántara, A.M.; Mohedano, M.L.; Chiva, R.; Celador-Lera, L.; Velázquez, E.; Prieto, A.; Dueñas, M.T.; Tamame, T.; López, P. (2021).
Lactic Acid Bacteria Isolated from Fermented Doughs in Spain Produce Dextrans and Riboflavin.
Foods 2021, 10(9), 2004.
Doi: 10.3390/foods10092004
Chiva, R., Celador-Lera, L., Uña, J.A., Jiménez-López, A., Espinosa-Alcantud, M., Mateos-Horganero, E., Vega, S., Santos, M.Á., Velázquez, E., Tamame, M. (2021)
Yeast biodiversity in fermented doughs and raw cereal matrices and the study of technological traits of selected strains isolated in Spain.
Microorganisms 2021; 47: 1-44.
Doi: 10.3390/microorganisms9010047
Martin-Marcos P, Zhou F, Karunasiri C, Zhang F, Dong J, Nanda J, Kulkarni SD, Sen ND, Tamame M, Zeschnigk M, Lorsch JR and Hinnebusch AG (2017)
eIF1A residues implicated in cancer stabilize translation preinitiation complexes and favor suboptimal initiation sites in yeast.
eLife 2017; 6: e31250
Ohmayer U, Gil-Hernández A, Sauert M, Martín-Marcos P, Tamame M, Tschochner H, Griesenbeck J and Milkereit P (2015)
Studies on the Coordination of Ribosomal Protein Assembly Events Involved in Processing and Stabilization of Yeast Early Large Ribosomal Subunit Precursors.
PLoS One Dec 7;10(12)
Chiva RA, Jiménez-López A, Espinosa M, Santos M A and Tamame M. (2014)
Nuevas levaduras para nuevos panes.
ALIMENTARIA 456: 38-46
Iglesias-Gato D, Martín-Marcos P, Santos MA, Hinnebusch AG, Alan G and Tamame M (2011)
Guanine nucleotide pool imbalance impairs multiple steps of protein synthesis and disrupts GCN4 translational control in Saccharomyces cerevisiae.
Genetics 187: 105-122
Martín-Marcos P, Hinnebusch AG and Tamame M (2007)
Ribosomal protein L33 is required for ribosome biogenesis, subunit joining and repression of GCN4 translation.
Mol. Cell. Biol. 27: 5968-5985

Research grants

NUTRIPANSALUD: CPP2021-00859 (2022-2024)
MCIN/AEI/10.13039/501100011033 y por la Unión Europea “NextGenerationEU” / PRTR
PANVITDEX: PDC2022-133562-100 (2022-2024)
TCUE/FEDER PROGRAMME Junta de Castilla y León and the University of Salamanca:
PROPAN: IPT-2012-1321-06000 (2012-2015)
INNOSTARPAN: RTC-2015-4391 (2015-2018)
INNOMICROVIN RTC-2017-6361-2 (2017-2021)
TCUE/FEDER PROGRAMME Junta de Castilla y León and the University of Salamanca:
(i) Lanzadera TCUE "Biomicrolevacer" (TCUE15-17_F2_002, 2017-2018)
(ii) Consorcios TCUE "Microbeia 2018", (TCUE15-17_F2_004, 2017)
(iii) Prueba de Concepto "2Star2Pan "(PC TCUE 15-17 F2 030 2017-18)
(iv)Prueba de Concepto "CICER4FOOD"(PC_TCUE21-23_037)
II Call for Research Projects aimed at providing technological solutions for the Primary Sector (Diputación de Salamanca, 2017-2018)