Fungal strains isolated from cork stoppers and the formation of 2,4,6-trichloroanisole involved in the cork taint of wine

ABSTRACT Cork taint is a musty or moldy off-odor in wine mainly caused by 2,4,6-trichloroanisole (2,4,6-TCA). We examined the role of 14 fungal strains isolated from cork samples in the production of 2,4,6-TCA by O methylation of 2,4,6-trichlorophenol (2,4,6-TCP). The fungal strains isolated belong to the genera Penicillium (four isolates); Trichoderma (two isolates); and Acremonium, Chrysonilia, Cladosporium, Fusarium, Mortierella, Mucor, Paecilomyces, and Verticillium (one isolate each). Eleven of these strains could produce 2,4,6-TCA when they were grown directly on cork in the presence of 2,4,6-TCP. The highest levels of bioconversion were carried out by the Trichoderma and Fusarium strains. One strain of Trichoderma longibrachiatum could also efficiently produce 2,4,6-TCA in liquid medium. However, no detectable levels of 2,4,6-TCA production by this strain could be detected on cork when putative precursors other than 2,4,6-TCP, including several anisoles, dichlorophenols, trichlorophenols, or other highly chlorinated compounds, were tested. Time course expression studies with liquid cultures showed that the formation of 2,4,6-TCA was not affected by a high concentration of glucose (2% or 111 mM) or by ammonium salts at concentrations up to 60 mM. In T. longibrachiatum the O methylation of 2,4,6-TCP was catalyzed by a mycelium-associated S-adenosyl-l-methionine (SAM)-dependent methyltransferase that was strongly induced by 2,4,6-TCP. The reaction was inhibited by S-adenosyl-l-homocysteine, an inhibitor of SAM-dependent methylation, suggesting that SAM is the natural methyl donor. These findings increase our understanding of the mechanism underlying the origin of 2,4,6-TCA on cork, which is poorly understood despite its great economic importance for the wine industry, and they could also help us improve our knowledge about the biodegradation and detoxification processes associated with chlorinated phenols.

Download Full-text

Fungal Diversity of Deteriorated Sparkling Wine and Cork Stoppers in Catalonia, Spain

Microorganisms ◽

10.3390/microorganisms8010012 ◽

2019 ◽

Vol 8 (1) ◽

pp. 12 ◽

Cited By ~ 2

Author(s):

Ernesto Rodríguez-Andrade ◽

Alberto M. Stchigel ◽

Josep Guarro ◽

José F. Cano-Lira

Keyword(s):

Fungal Diversity ◽

New Genus ◽

Potato Dextrose Agar ◽

Sparkling Wine ◽

Fungal Contamination ◽

Future Studies ◽

Aspergillus Section Nidulantes ◽

Cork Taint ◽

Possible Cause ◽

Cork Stoppers

Filamentous fungi are rarely reported as responsible for spoiling wine. Cork taint was detected in sparkling wine; therefore, we investigated fungal contamination as a possible cause of organoleptic alteration. Spoiled wine was filtered and membranes were plated onto potato dextrose agar (PDA). The cork stoppers used for sealing bottles were cut and also plated onto PDA. Fungal strains were phenotypically characterized and molecularly identified by sequencing of a fragment of the 28S nrRNA gene (LSU) and (occasionally) by other additional molecular markers. Twenty-seven strains were isolated and sixteen species were identified, all of them belonging to the phylum Ascomycota. The fungi isolated from wine were three species of Aspergillus section Nidulantes, a species of Penicillium section Exicaulis and Beauveria bassiana. Candida patagonica was isolated from both sort of samples, and the fungi isolated from cork stoppers were Altenaria alternata and Cladosporium cladosporioides. Surprisingly, most of the taxa recovered from the cork stoppers and/or wine were new to the science: a new genus (Dactylodendron) and seven new species belonging to the genera Cladophialophora, Dactylodendron, Kirschsteiniothelia, Rasamsonia, and Talaromyces. Future studies could let us know if these fungi would be able to produce compounds responsible for cork taint.

Download Full-text

Presence of cork-taint responsible compounds in wines and their cork stoppers

European Food Research and Technology ◽

10.1007/s002170000193 ◽

2000 ◽

Vol 211 (4) ◽

pp. 257-261 ◽

Cited By ~ 65

Author(s):

A. Peña-Neira ◽

B. Fernández de Simón ◽

M. C. García-Vallejo ◽

T. Hernández ◽

E. Cadahía ◽

...

Keyword(s):

Cork Taint ◽

Cork Stoppers

Download Full-text

Synthesis, photosensitization and antimicrobial activity evaluation of some novel Merocyanine dyes

10.31221/osf.io/yv273 ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antimicrobial Activity ◽

Aspergillus Flavus ◽

Elemental Analysis ◽

Cyanine Dyes ◽

Fungal Strains ◽

Activity Evaluation ◽

Visible Spectra ◽

Merocyanine Dyes

Novel acyclic and cyclic merocyanine dyes derived from the nucleu of furo [(3,2-d) pyrazole; ( d 2 , 3 )imidazole]were prepared. The electronic visible absorptionspectra of all the synthesized new cyanine dyes were examined in 95% ethanolsolution to evaluate their photosensitization properties. Antibacterial andantifungal activities for some selected dyes were tested against various bacterialand fungal strains (Escherichia coli, Staphylococcus aureus, Aspergillus flavus andCandida albicans) to evaluate their antimicrobial activity. Structural identificationwas carried out via elemental analysis, visible spectra, IR and 1H NMRspectroscopic data.

Download Full-text