Part of Thermo Fisher Scientific
Organisms this product works with:
Other products used in the isolation of Yeasts:
WL NUTRIENT BROTH
Code: CM0501
A liquid medium for use in the control of brewing and other fermentation processes.
Typical Formula* | gm/litre |
Yeast extract | 4.0 |
Tryptone | 5.0 |
Glucose | 50.0 |
Potassium dihydrogen phosphate | 0.55 |
Potassium chloride | 0.425 |
Calcium chloride | 0.125 |
Magnesium sulphate | 0.125 |
Ferric chloride | 0.0025 |
Manganese sulphate | 0.0025 |
Bromocresol green | 0.022 |
pH 5.5 ± 0.2 @ 25°C |
|
Directions
Dissolve 60g in 1 litre of distilled water. Mix well and distribute into containers. Sterilise by autoclaving at 121°C for 15 minutes.
The pH may be raised to 6.5 by the addition of 1% w/v sodium bicarbonate solution. Adding 0.004 grams/litre of cycloheximide per litre (4ml SR0222) will form WL Differential Broth. Note the precautions to be taken under HAZARDS.
Description
WL Nutrient Broth is based on the formulation of Green and Gray1 and is used where there are advantages for broth media e.g. using larger samples of liquid products or for enrichment cultures with cycloheximide.
Addition of 0.004 grams/litre of cycloheximide suppresses yeast growth and renders the medium selective for bacterial contaminants. Adjustment of the medium to pH 6.5 facilitates growth of bakers’ and distillers’ yeasts; the medium at pH 5.5 is used for growth of bakers’ yeasts.
Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.
Appearance
Dehydrated medium: Pale blue coloured, free-flowing powder
Prepared medium: Blue/green coloured solution
Quality control
Positive controls: w/o cycloheximide | Expected results |
Saccharomyces cerevisiae ATCC® 9763 * | Turbid growth |
Negative control: | |
Uninoculated medium | No change |
Positive control: with cycloheximide | |
Escherichia coli ATCC® 25922 * | Turbid growth |
Negative control: | |
Saccharomyces cerevisiae ATCC® 9763 * | No growth |
Precautions
When handling cycloheximide observe the precautions to be taken under HAZARDS.
References
1. Green S. R. and Gray P. P. (1950) Wallerstein Lab. Comm. 13. 357.
2. Hall Jean F. (1971) J. Inst. Brewing 77. 513-516.