18 research outputs found

    Selected Schizosaccharomyces pombe Strains Have Characteristics That Are Beneficial for Winemaking

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    At present, wine is generally produced using Saccharomyces yeast followed by Oenococus bacteria to complete malolactic fermentation. This method has some unsolved problems, such as the management of highly acidic musts and the production of potentially toxic products including biogenic amines and ethyl carbamate. Here we explore the potential of the fission yeast Schizosaccharomyces pombe to solve these problems. We characterise an extensive worldwide collection of S. pombe strains according to classic biochemical parameters of oenological interest. We identify three genetically different S. pombe strains that appear suitable for winemaking. These strains compare favourably to standard Saccharomyces cerevisiae winemaking strains, in that they perform effective malic acid deacidification and significantly reduce levels of biogenic amines and ethyl carbamate precursors without the need for any secondary bacterial malolactic fermentation. These findings indicate that the use of certain S. pombe strains could be advantageous for winemaking in regions where malic acid is problematic, and these strains also show superior performance with respect to food safety

    Kinetic constraints and features imposed by the immobilization of enzymes onto solid matrices: A key to advanced biotransformation

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    1045-1051The kinetics of immobilized enzymes can not be analyzed by means of the simple Michaelis-Menten concept, which generally fails to describe the immobilized state due to both its probable barriers, and because the active concentration of the enzyme approaches, or even exceeds this of its substrate(s). In such cases, the various experimental data are usually treated by complex rate equations comprising too many parameters acquiring different natures and meanings, depending on both the properties of the immobilization state and the experimental conditions; thus, more likely, only apparent values of the Michaelis-Menten kinetic parameters can be estimated experimentally. Likewise, immobilization is often a key method in optimizing the operational performance of enzymes, in both laboratory and industrial scale, and affects considerably the kinetics in non-aqueous and non-conventional media due to several issues as the structural changes of the enzyme molecule, the heterogeneity of the system, and the partial or total absence of water. In this work a theoretical approach is described on the formulation of simplified rate equations, reflecting also the actual mass balances of the reactants, in the case where esterification synthetic reactions are catalyzed by immobilized lipases, in either a non-aqueous organic solvent or in a non-solvent system

    Correction to: Molecular, biochemical and kinetic analysis of a novel, thermostable lipase (LipSm) from Stenotrophomonas maltophilia Psi‑1, the first member of a new bacterial lipase family (XIX)

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    We have recently (8th February 2018) published our article entitled “Molecular, biochemical and kinetic analysis of a novel, thermostable lipase (LipSm) from Stenotrophomonas maltophilia Psi-1, the first member of a new bacterial lipase family (XVIII)” [1]. While our manuscript was going through the final stages of publication, an article by Samoylova et al. [2] was published (12th January 2018) in the journal Extremophiles, entitled “Cloning, expression and characterization of the esterase estUT1 from Ureibacillus thermosphaericus which belongs to a new lipase family XVIII”. Since we could not have known of the work of Samoylova et al. [2] when we submitted our manuscript, and in order to avoid confusion in the scientific community, we propose to reclassify LipSm as the first characterized member of the new bacterial lipase family XIX. Therefore throughout our article [1] “lipase family XVIII” should read “lipase family XIX” (title included)

    Effect of fungicides on the yeast population during spontaneous fermentation in the vinification of monastrell grapes

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    © 2020. Elsevier This document is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the published version of a published work that appeared in final form in LWT - Food Science and TechnologyThe influence of six fungicides on indigenous yeasts of grape var. Monastrell, after performing two treatments (Good Agricultural Practices-GAP and Critical Agricultural Practices-CAP), was studied. Fungicide residues have been determined using a method of multi-residual extraction that uses QuEChERS and liquid chromatography in tandem with triple quadrupole mass spectrometry. Identification of yeast was carried out by PCR and subsequent sequencing. The fungicide residues are below the EU maximum residue limits (MRLs) established in wine grapes. At the beginning and during the fermentation, most of the treated samples show counts (CFU/mL) higher than the control test (20–30% more), even in the most unfavorable conditions (treated the same day of harvest). It is noteworthy the absence of Hanseniaspora uvarum and the presence of Clavispora lusitaniae, Debaryomyces hansenii and Metschnikowia pulcherrima. Nevertheless, no fungicide either under treatment inhibits fermentation or delays it. Moreover, the evolution of yeast populations found during fermentation follows the normal sequence of species. This research might be of interest for scientists and companies working on either basic or production aspects respectively of the winemaking process
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