Ready-to-use media
Brettanomyces Agar
Solid culture medium for the differential isolation of Brettanomyces/Dekkera spp. from spoiled wines.
- Cat. No.
- LC-4739
- Category
- Ready-to-use media
- Format
- 30 water plates, 55 mm
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 2 months
- Minimum order
- 35 packs
- Also available
- Dehydrated medium, 1 format (LC-2006)
Brettanomyces Agar derives from DBDM (Rodrigues et al., 2001), whose formula has been profoundly modified to achieve reliable results with shorter incubation periods. The concentration of ethanol has been reduced and glucose has been added as a carbon and energy source; as nitrogen source, the yeast nitrogen base has been supplemented with a mixture of peptone, malt extract and yeast extract, and with a small amount of thiamine as growth factor. Chloramphenicol hinders bacterial growth and cycloheximide fungal growth. Bromocresol green is an indicator of acid production and p-coumaric acid is included as a precursor in the production of ethyl phenols that give the characteristic mousy off-flavor.
Key features
Applications
Enrichment of Brettanomyces.
Industry
Alcoholic beverages.
Presentation
30 prepared filtration plates, 55 mm, double wrapping, with 9 ± 1 mL.
Packaging
1 box containing 5 plastic bags with 6 plates of 55 mm/bag.
Description and technique
Description
Brettanomyces/Dekkera (anamorph/teleomorph or, if preferred, asexual/sexual) is a group of slow-growing yeasts, resistant to high concentrations of ethanol and able to ferment the residual sugars in fermented products such as wine, beer and other alcoholic beverages. This group of yeasts also has a strong vinyl phenol reductase activity, with production of various ethyl phenols to which different olfactory descriptors such as "stable smell", "mousy smelling" and "horse urine smell" are attributed, depending on their nature and concentration. However, at low concentrations these ethyl phenols may confer special and positively valued characteristics in certain types of wine and beer.
Technique
Collect, dilute and prepare samples and volumes as required according to specifications, directives, official standard regulations and/or expected results.
Inoculate an aliquot of the sample on the medium surface and incubate at 22-25 °C for 5-7 days. Longer incubations may cause the overgrowth of opportunistic microbiota (especially molds resistant to cycloheximide), which hinder the correct reading of results.
Dekkera/Brettanomyces colonies appear small (2-3.5 mm in diameter), bright, very convex, nearly hemispherical, with straight or lobed edge, creamy consistency and color between beige and greenish yellow, with a yellow zone because the acid production turns the indicator from greenish-blue to yellow.
Dekkera/Brettanomyces colonies grown on this culture medium give off a characteristic smell due to the ethyl phenols produced.
Presentation
| Presentation | 30 prepared filtration plates, 55 mm, double wrapping |
|---|---|
| Filling | 9 ± 1 mL |
| Packaging | 1 box containing 5 plastic bags with 6 plates of 55 mm/bag. |
Composition
| Ingredient | g/L |
|---|---|
| D(+)-Glucose | 10.000 |
| Peptone | 5.000 |
| Yeast nitrogen base | 3.000 |
| Malt extract | 3.000 |
| Yeast extract | 3.000 |
| Chloramphenicol | 0.100 |
| p-Coumaric acid | 0.100 |
| Thiamine | 0.020 |
| Cycloheximide | 0.010 |
| Bromocresol green | 0.022 |
| Agar | 20.00 |
Quality control
Physical/chemical control
| Color | Light green |
|---|---|
| pH | 5.3 ± 0.2 at 25 °C |
Microbiological control
Loop spreading.
Aerobiosis. Incubation at 22-25 °C for 5-7 days for yeasts and moulds.
| Microorganism | Growth |
|---|---|
| Dekkera anomalaATCC 10562 | Good |
| Dekkera bruxellensisATCC 36234 | Good |
| S. cerevisiaeATCC 9763, WDCM 00058 | Inhibited |
| Enterococcus faecalisATCC 29212, WDCM 00087 | Inhibited |
| Escherichia coliATCC 8739, WDCM 00012 | Inhibited |
Sterility control
Incubation 48 hours at 30-35 °C and 48 hours at 20-25 °C: NO GROWTH.
Check at 7 days after incubation in same conditions.
Bibliography
- BARNETT, J.A., R.W. PAYNE and D. YARROW (1983) Yeasts: Characteristics and identification. Cambridge University Press. Cambridge. UK.
- BENITO, S., F. PALOMERO, A. MORATA, F. CALDERON, M.C. GONZALEZ and J.A. SUAREZ-LEPE (2007) Medios selectivo-diferenciales en la detección y aislamiento de Brettanomyces/Dekkera. Ponencia en el XIII Congreso Nacional de Enólogos. Logroño, 3-5 mayo.
- DIAS, L., S. DIAS, T. SANCHO, H. STENDER, A. QUEROL, M. MALFEITO-FERREIRA, and V. LOUREIRO (2003) Identification of yeasts isolated from wine-related environments and capable of producing 4-ethylphenol. Food Microbiol 20:567-574.
- EDWARDS, C.G. (2005) Illustrated guide to microbes and sediments in wine, beer and juice. WineBugs LLC, Pullman, Washington, USA.
- HERNANDEZ, J. and F. BARBERO (2007) Brettanomyces bruxelensis en bodega. VinoTeQ 3:20-24.
- KRFEGER-van RIJ, N.J.W. (1984) The yeast, a taxonomic study. 3rd ed. Elsevier Sci Pub. Amsterdam.
- MORNEAU, A.D., J.M. ZUEHLKE and C.G. EDWARDS (2011) Comparison of media formulations used to selectively cultivate Dekkera/Brettanomyces. Lett. Appl. Microbiol. 53:460-465.
- NAVASCUÉS LOPEZ-CORDON, E. (2009) Control y detección en Bodega de Brettanomyces. Winemaking Update. Revista de Enologia. 1:1-5.
- RENOUF, V., A. LONVAUD-FUNEL (2007) Development of an enrichment medium to detect Dekkera/Brettanomyces bruxellensis, a spoilage wine yeast, on the surface of grape berries. Microbiol. Res. 162(2):154-167.
- RODRIGUES, N., G. GONÇALVES, S. PEREIRA-da-SILVA, M. MALFEITO-FERREIRA and V. LOUREIRO (2001) Development and use of a new medium to detect yeasts of the genera Dekkera/Brettanomyces. J. Appl. Microbiol. 90:588-599.
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