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Muhl JR, Pilkington LI, Fedrizzi B, Deed RC. Insights into the relative contribution of four precursors to 3-sulfanylhexan-1-ol and 3-sulfanylhexylacetate biogenesis during fermentation. Food Chem 2024; 449:139193. [PMID: 38604037 DOI: 10.1016/j.foodchem.2024.139193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/13/2024]
Abstract
The desirable wine aroma compounds 3-sulfanylhexan-1-ol (3SH) and 3-sulfanylhexyl acetate (3SHA) are released during fermentation from non-volatile precursors present in the grapes. This work explores the relative contribution of four precursors (E-2-hexenal, 3-S-glutathionylhexan-1-ol, 3-S-glutathionylhexanal, and 3-S-cysteinylhexan-1-ol) to 3SH and 3SHA. Through the use of isotopically labelled analogues of these precursors in defined fermentation media, new insights into the role of each precursor have been identified. E-2-Hexenal was shown to contribute negligible amounts of thiols, while 3-S-glutathionylhexan-1-ol was the main precursor of both 3SH and 3SHA. The glutathionylated precursors were both converted to 3SHA more efficiently than 3-S-cysteinylhexan-1-ol. Interestingly, 3-S-glutathionylhexanal generated 3SHA without detectable concentrations of 3SH, suggesting possible differences in the way this precursor is metabolised compared to 3-S-glutathionylhexan-1-ol and 3-S-cysteinylhexan-1-ol. We also provide the first evidence for chemical conversion of 3-S-glutathionylhexan-1-ol to 3-S-(γ-glutamylcysteinyl)-hexan-1-ol in an oenological system.
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Affiliation(s)
- Jennifer R Muhl
- School of Chemical Sciences, The University of Auckland | Waipapa Taumata Rau, 23 Symonds Street, Auckland, New Zealand.
| | - Lisa I Pilkington
- School of Chemical Sciences, The University of Auckland | Waipapa Taumata Rau, 23 Symonds Street, Auckland, New Zealand; Te Pūnaha Matatini, Auckland 1010, New Zealand.
| | - Bruno Fedrizzi
- School of Chemical Sciences, The University of Auckland | Waipapa Taumata Rau, 23 Symonds Street, Auckland, New Zealand.
| | - Rebecca C Deed
- School of Chemical Sciences, The University of Auckland | Waipapa Taumata Rau, 23 Symonds Street, Auckland, New Zealand; School of Biological Sciences, The University of Auckland | Waipapa Taumata Rau, 3 Symonds Street, Auckland, New Zealand.
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Gardner JM, Alperstein L, Walker ME, Zhang J, Jiranek V. Modern yeast development: finding the balance between tradition and innovation in contemporary winemaking. FEMS Yeast Res 2023; 23:6762920. [PMID: 36255399 PMCID: PMC9990983 DOI: 10.1093/femsyr/foac049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/11/2022] [Accepted: 02/01/2023] [Indexed: 11/13/2022] Open
Abstract
A key driver of quality in wines is the microbial population that undertakes fermentation of grape must. Winemakers can utilise both indigenous and purposefully inoculated yeasts to undertake alcoholic fermentation, imparting wines with aromas, flavours and palate structure and in many cases contributing to complexity and uniqueness. Importantly, having a toolbox of microbes helps winemakers make best use of the grapes they are presented with, and tackle fermentation difficulties with flexibility and efficiency. Each year the number of strains available commercially expands and more recently, includes strains of non-Saccharomyces, strains that have been improved using both classical and modern yeast technology and mixed cultures. Here we review what is available commercially, and what may be in the future, by exploring recent advances in fermentation relevant strain improvement technologies. We also report on the current use of microbes in the Australian wine industry, as reported by winemakers, as well as regulations around, and sentiment about the potential use of genetically modified organisms in the future.
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Affiliation(s)
- Jennifer M Gardner
- Department of Wine Science, School of Agriculture, Food and Wine, The University of Adelaide, PMB1, Glen Osmond 5064, South Australia, Australia
| | - Lucien Alperstein
- Department of Wine Science, School of Agriculture, Food and Wine, The University of Adelaide, PMB1, Glen Osmond 5064, South Australia, Australia
| | - Michelle E Walker
- Department of Wine Science, School of Agriculture, Food and Wine, The University of Adelaide, PMB1, Glen Osmond 5064, South Australia, Australia
| | - Jin Zhang
- Department of Wine Science, School of Agriculture, Food and Wine, The University of Adelaide, PMB1, Glen Osmond 5064, South Australia, Australia
| | - Vladimir Jiranek
- Department of Wine Science, School of Agriculture, Food and Wine, The University of Adelaide, PMB1, Glen Osmond 5064, South Australia, Australia.,Australian Research Council Training Centre for Innovative Wine Production, Urrbrae 5064, South Australia, Australia
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Novel breeding method, matα2-PBT, to construct isogenic series of polyploid strains of Saccharomyces cerevisiae. J Biosci Bioeng 2022; 133:515-523. [PMID: 35393168 DOI: 10.1016/j.jbiosc.2022.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/14/2022] [Accepted: 02/03/2022] [Indexed: 11/22/2022]
Abstract
How ploidy is determined in organisms is an important issue in bioscience. Polyploidy is believed to be relevant to useful traits of domesticated plants and microorganisms. As such, polyploidy is central to many applications in biotechnology. However, studies of polyploidy are poorly advanced because no methodologies to construct desired polyploid have been developed for any organism. Herein we describe the development of a novel breeding technology, matα2-PBT, to generate polyploid strains of Saccharomyces cerevisiae. S. cerevisiae has two mating types, a and α, determined by MATa and MATα gene each of which consists of a1 and a2 and α1 and α2 cistrons. This novel technology exploits an interesting feature of a specific mutation, matα2-102, in the MATα2 gene. Unlike the MATα wild-type strain, which gives a non-mating phenotype when mated with MATa cells, the matα2-102 strain confers an α mating-type to a-type strains when mated with a-type strains. We constructed plasmid with the cloned matα2-102 mutant gene. An a-type cells harboring this plasmid displayed an α mating-type and mated with a-type cells. Because the resultant hybrid displays an α mating-type, it can mate again with a-type cells. By repeating this procedure, we have constructed an isogenic series of haploid to tetraploid of S. cerevisiae. Although whether even higher polyploid than tetraploid can be constructed by using this technology remains to be determined in the future, we believe that it became possible for the first time with matα2-PBT method to investigate whether higher polyploid than tetraploid can be constructed.
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