Departamento de Microbiología
http://hdl.handle.net/10396/122
2024-03-28T14:24:07ZGlycerol photoreforming for photocatalytic hydrogen production on binary and ternary Pt-g-C3N4-TiO2 systems: a comparative study
http://hdl.handle.net/10396/27456
Glycerol photoreforming for photocatalytic hydrogen production on binary and ternary Pt-g-C3N4-TiO2 systems: a comparative study
Herrera-Beurnio, M. Carmen; López-Tenllado, Francisco J.; Hidalgo-Carrillo, J.; Martín-Gómez, Juan; Estévez, R.; Urbano, Francisco José; Marinas, Alberto
Photocatalytic hydrogen production using two sacrificial agents (triethanolamine and glycerol) was conducted on several binary (Pt/TiO2 and Pt/g-C3N4) and ternary systems (Pt on a heterojunction between TiO2 and g-C3N4 (Pt/(g-C3N4-TiO2) and on a physical mixture of semiconductors (Pt/(TiO2 +g-C3N4)). Reactions were carried out under visible light (450 nm) and UV (365 nm) radiation, from 10% (v/v) and 0.5% (v/v) sacrificial agent aqueous solutions, hydrogen production values being ca- 2–3 times greater in the former case. For visible light, the heterojunction was the most active system using triethanolamine whereas Pt/TiO2 system and glycerol was the best option under UV radiation. All in all, the highest hydrogen production value from a 10% (v/v) glycerol in water solution was on Pt/TiO2 (named Ptuv/Ti), under UV light, yielding around 165 mmol H2·gcat−1·after 6 h (that is, ca. 27.5 mmol·gcat−1·h−1). Hydrogen photoproduction studies from glyceraldehyde, dihydroxyacetone, and glycerol either alone or in binary mixtures (i.e., competitive reactions) cast further light on the glycerol reaction mechanism. Results evidenced that the adsorption strength on the catalysts follows the sequence glyceraldehyde > dihydroxyacetone > glycerol, adsorption of the former being particularly high on the heterojunction. Reactions were ca. twice as fast on Pt/TiO2 as on the Pt/(g-C3N4-TiO2) heterojunction and even though initial stages of the mechanism seems to differ a bit for the semiconductors, there is a hydrogen production value from which mechanism is apparently the same on both solids.
2024-01-01T00:00:00ZChemometric differentiation of white wines from a low-aromatic grape obtained by spontaneous fermentation, enriched with non-Saccharomyces, or with a high-Glutathione-producing Saccharomyces yeast
http://hdl.handle.net/10396/26379
Chemometric differentiation of white wines from a low-aromatic grape obtained by spontaneous fermentation, enriched with non-Saccharomyces, or with a high-Glutathione-producing Saccharomyces yeast
Muñoz-Castells, Raquel; Moreno, Juan; García-Martínez, Teresa; Mauricio, Juan C.; Moreno-García, Jaime
This work focuses on the establishment of analytical and sensory differences between young wines obtained from the same grape must fermented using different strategies. The main purpose is to provide winemakers with objective criteria to help them to choose the best fermentation method to obtain the desired wine characteristics. The effects of four strategies were tested: a spontaneous fermentation with wild yeasts (WYs) and the addition of starter cultures of Lachancea thermotolerans (LT), Metschnikowia pulcherrima (MP), and a Saccharomyces cerevisiae strain that is an overproducer of glutathione (SC) in different batches of the same must of the Pedro Ximénez white grape. The analytical results obtained show as the LT wine has the highest glutathione content, while the lowest ethanol concentrations. The use of chemometric tools applied to the volatile compounds allowed to differentiate the four wines by a principal component analysis (PCA) and the identification of 27 key compounds. The four wines did not show statistical differences in their smell or taste attributes and only the LT wine was visually differentiated from the rest.
2023-01-01T00:00:00ZFirst Proteomic Approach to Identify Cell Death Biomarkers in Wine Yeasts during Sparkling Wine Production
http://hdl.handle.net/10396/19066
First Proteomic Approach to Identify Cell Death Biomarkers in Wine Yeasts during Sparkling Wine Production
Porras-Agüera, Juan Antonio; Moreno-García, Jaime; Mauricio, Juan C.; Moreno, Juan; García-Martínez, Teresa
Apoptosis and later autolysis are biological processes which take place in Saccharomyces cerevisiae during industrial fermentation processes, which involve costly and time-consuming aging periods. Therefore, the identification of potential cell death biomarkers can contribute to the creation of a long-term strategy in order to improve and accelerate the winemaking process. Here, we performed a proteomic analysis based on the detection of possible apoptosis and autolysis protein biomarkers in two industrial yeast strains commonly used in post-fermentative processes (sparkling wine secondary fermentation and biological aging) under typical sparkling wine elaboration conditions. Pressure had a negatively effect on viability for flor yeast, whereas the sparkling wine strain seems to be more adapted to these conditions. Flor yeast strain experienced an increase in content of apoptosis-related proteins, glucanases and vacuolar proteases at the first month of aging. Significant correlations between viability and apoptosis proteins were established in both yeast strains. Multivariate analysis based on the proteome of each process allowed to distinguish among samples and strains. The proteomic profile obtained in this study could provide useful information on the selection of wine strains and yeast behavior during sparkling wine elaboration. Additionally, the use of flor yeasts for sparkling wine improvement and elaboration is proposed.
2019-01-01T00:00:00ZEffect of Bay Leaves Essential Oil Concentration on the Properties of Biodegradable Carboxymethyl Cellulose-Based Edible Films
http://hdl.handle.net/10396/18918
Effect of Bay Leaves Essential Oil Concentration on the Properties of Biodegradable Carboxymethyl Cellulose-Based Edible Films
Rincón, E.; Serrano, Luis; Balu, Alina M.; Aguilar, José J.; Luque, Rafael; García, Araceli
Films containing bay leaves essential oils (BEOs) were prepared and evaluated for edible packaging applications. The BEOs were extracted by the Soxhlet method, using ethanol or methanol as organic solvent. Then, films were prepared by “solvent casting” technique using carboxymethyl cellulose (CMC), with different concentrations for the as-obtained BEOs (from 1% to 30% wt.). The resulting films were characterized to evaluate their physical (thickness, moisture content, water solubility and water vapor permeability), optical (transparency and UV-light barrier), mechanical (tensile strength and elongation at break), antioxidant and antimicrobiological properties Attractive films were obtained for food active packaging applications, as they presented a high antioxidant activity (up to 99%) and total phenolic content, and good barrier properties against water vapor (50% improved of CMC) in the case of CMC-film containing 15% wt. ethanolic extract. Related to optical properties, UV-light barrier effect was increased (almost 100% of protection) avoiding typical lipids oxidation in food systems. High water solubility (93%) was also found, ensuring also their biodegradability. Moreover, it was demonstrated that developed films inhibit microorganisms’ growth (Escherichia coli and Candida glabrata), this avoiding an early food oxidation.
2019-01-01T00:00:00Z