WL Nutrient Agar

suitable for microbiology, NutriSelect® Plus

Wallerstein Laboratory Nutrient Agar

Quality Level





shelf life

limited shelf life, expiry date on the label


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


nonselective and differential for Candida spp.
nonselective and differential for Escherichia coli
nonselective and differential for Lactobacillus spp.
nonselective and differential for Pichia spp.
nonselective and differential for Proteus spp.
nonselective and differential for Saccharomyces spp.
nonselective and differential for Zygosaccharomyces spp.
nonselective and differential for bacteria (General Media)
nonselective and differential for coliforms
nonselective and differential for molds (General Media)
nonselective and differential for yeasts (General Media)

Related Categories

General description

WL (Walerstein Laboratory) media follow the formula described by Green and Gray for the examination of materials related to brewing and for industrial fermentations containing mixed flora of yeasts and bacteria. Yeast extract is a source of vitamins, amino acids and trace elements. Casein enzymic hydrolysate provides nitrogen, amino acids and carbon. Dextrose is the main carbon and energy source. Potassium phosphate is the buffering agent. Several salts in the medium provide essential ions and help to maintain osmotic balance. Bromcresol green acts as pH indicator and agar as solidifying agent. WL Nutrient Agar is used for the examination of materials encountered in brewing and for industrial fermentations containing mixed flora of yeasts and bacteria.


WL Nutrient Agar is suitable:
  • for reviving yeast stock cultures and for population dynamics studies post fermentation
  • for morphological characterization of yeast isolated from cheese
  • for plating fermented wine for yeast species isolation

Preparation Note

Suspend 80.25 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.

Legal Information

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
The rapid detection of brewery spoilage micro-organisms
Harrison J, et al.
Journal of the Institute of Brewing, 80(4), 390-398 (1974)
Selection of autochthonous Saccharomyces cerevisiae strains for production of typical Pinot Gris wines.
Schvarczova E, et al.
Journal of Food & Nutrition Research, 56(4) (2017)
The impact of Saccharomyces cerevisiae on a wine yeast consortium in natural and inoculated fermentations
Bagheri B, et al.
Frontiers in Microbiology, 8, 1988-1988 (2017)
Paper read at American Society of Brewing Chemists Meeting
Green, SR and Gray, PP
Wallerstein Laboratories Communications, 12, 43-43 (1950)
Characterisation of yeast flora isolated from an artisanal Portuguese ewe's cheese
Malfeito-Ferreira M, et al.
International Journal of Food Microbiology (2000)
Molecular biology-based methods, like PCR, can be used for lactobacilli detection. However, they are often quite expensive. We provide a revolutionary molecular biology method that is rapid, easy, and cost-effective.
Read More
Traditional methods are based morphology, staining methods, enzyme reactions (metabolism) and diverse media.
Read More
Today, diverse studies report the benefits of probiotics, such as inhibitory effects on pathogens, aid in the management or prevention of chronic intestinal inflammatory diseases or atopic syndromes, and support to the immune system. Potential beneficial applications abound, researchers continue to evaluate the effictiveness and clarify the mechanisms of action of probiotics.
Read More

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

Contact Technical Service

Social Media

LinkedIn icon
Twitter icon
Facebook Icon
Instagram Icon


Research. Development. Production.

We are a leading supplier to the global Life Science industry with solutions and services for research, biotechnology development and production, and pharmaceutical drug therapy development and production.

© 2021 Merck KGaA, Darmstadt, Germany and/or its affiliates. All Rights Reserved.

Reproduction of any materials from the site is strictly forbidden without permission.