WL Differential Agar

suitable for microbiology, NutriSelect® Plus

WLD Agar, Wallerstein Differential Agar

Quality Level





shelf life

limited shelf life, expiry date on the label


actidione (cycloheximide), 0.004 g/L
agar, 20 g/L
bromocresol green, 0.022 g/L
calcium chloride, 0.125 g/L
casein enzymic hydrolysate, 5 g/L
dextrose, 50 g/L
ferric chloride, 0.0025 g/L
magnesium sulfate, 0.125 g/L
manganese sulfate, 0.0025 g/L
monopotassium phosphate, 0.55 g/L
potassium chloride, 0.425 g/L
yeast extract, 4 g/L


NutriSelect® Plus


bioburden testing: suitable
microbiological culture: suitable
microbiology: suitable

final pH

5.5±0.2 (25 °C)

Featured Industry

Food and Beverages


selective and differential for Escherichia coli
selective and differential for Lactobacillus spp.
selective and differential for Proteus spp.
selective and differential for bacteria (General Media)
selective and differential for coliforms

Related Categories

General description

WL (Wallerstein Laboratory) Differential Agar, modified is formulated as described by Green and Gray for the examination of materials encountered in brewing and for industrial fermentations containing mixed flora of yeasts and bacteria. WL Differential Agar helps in selective isolation and enumeration of bacteria encountered in breweries and industrial fermentations.


WL Differential Agar has been used for the enumeration of Kluyveromyces marxianus culture.

Preparation Note

Suspend 80.26 g in 1 litre distilled water. Boil to dissolve the medium completely. Sterilize by autoclaving at 121°C for 15 minutes. If desired, to obtain a pH of 6.5, add 1% solution of sodium bicarbonate.


We offer two media types: the superior granulated GranuCult® and the cost-efficient powdered NutriSelect® culture media, depending on your needs.
The designations basic, plus, or prime are added to indicate the quality control level, from basic quality control to standard QC plus to prime for full regulatory compliance.

Legal Information

GRANUCULT is a registered trademark of Merck KGaA, Darmstadt, Germany
NutriSelect is a registered trademark of Merck KGaA, Darmstadt, Germany

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


NONH for all modes of transport

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis

Certificate of Origin

A differential procedure for bacteriological studies useful in the fermentation industry
Green SR and Gray PP
Archives of Biochemistry and Biophysics, 32(1), 59-69 (1951)
Interactions between Kluyveromyces marxianus and Saccharomyces cerevisiae in tequila must type medium fermentation
Lopez CLF, et al.
World Journal of Microbiology & Biotechnology, 30(8), 2223-2229 (2014)
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Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

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