YPG Powder for 0.5 L

Quick Answer: YPG Powder for 0.5 L is a dehydrated culture medium, measured to make half a litre, used to grow yeasts such as Saccharomyces cerevisiae. The letters usually stand for yeast extract, peptone and glucose, the three nutrient sources of the classic rich yeast medium.

What Goes into a YPG Medium

In YPG powder, yeast extract supplies vitamins and nitrogen compounds, peptone provides amino acids and short peptides, and glucose is the carbon and energy source that yeast ferments. Many labs know the same recipe as YPD, with D for dextrose, another name for glucose. A few research protocols use YPG to mean glycerol instead of glucose, a carbon source yeast can respire but not ferment, so buyers planning respiration-specific work should check the formulation.

This pack is measured to prepare 0.5 L of medium. Whether that medium sets as a gel depends on whether agar is part of the powder: a broth is used in flasks and tubes for growth and fermentation studies, while an agar version is poured into Petri dishes for colonies. The title does not say which, so it is listed below as a detail to confirm.

Keep the unopened powder dry. Peptone and yeast extract absorb moisture from the air and cake, which makes weighing and dissolving slower and less even.

Yeast Practicals That Use YPG

• Culturing baker’s yeast from a dried yeast packet to teach aseptic technique
• Growth curves: sampling a broth culture over time and counting cells with a haemocytometer or reading turbidity on a colorimeter
• Fermentation experiments that collect carbon dioxide from yeast broth at different temperatures
• Growing fresh cells to watch budding under the microscope, alongside a yeast budding prepared slide
• Streaking for single colonies on an agar version, for example to compare two yeast strains

Specifications

Preparing and Storing the Medium

• Dissolve the powder in distilled or deionised water, warming gently while stirring, then make up to 0.5 L before sterilising.
• Autoclave using the cycle your lab uses for nutrient media; overheating a glucose medium darkens it as the sugar caramelises and reacts with the peptone.
• Store the closed container in a cool, dry place away from light, and discard powder that has changed colour or set hard.
• Label prepared plates or bottles with the date, keep them refrigerated and let them reach room temperature before inoculating.

Why Choose LabEquip

Microbiology teachers in schools, colleges and pharmacy departments order YPG powder alongside the dishes and loops needed to use it. LabEquip lists it in General Lab Products near consumables such as plastic Petri dishes; send class numbers and the number of packs through the contact page.

Frequently Asked Questions

What is the difference between YPG and YPD medium?

In most teaching catalogues they are the same recipe: yeast extract, peptone and a sugar. D stands for dextrose and G for glucose, which are the same sugar. In some research labs YPG means glycerol instead, used to test respiration because yeast cannot ferment glycerol.

Can bacteria grow on YPG?

Many bacteria grow well on a rich medium like this, which is why aseptic technique matters. YPG is not selective, so airborne or skin bacteria that reach the plate grow alongside the yeast. Research labs sometimes add an antibiotic when only yeast should grow.

Does YPG powder need to be autoclaved?

Yes. After dissolving the powder, sterilise the medium before use, usually by autoclaving. Unsterilised medium is overgrown by bacteria and moulds within a day or two at room temperature, which makes any yeast result meaningless.

What temperature suits Saccharomyces cerevisiae on YPG?

Around 30 °C is the usual growth temperature, and room temperature also works, more slowly. Growth falls away sharply as temperature approaches 40 °C, which is itself a useful variable to test in a fermentation practical.

Can I add agar to make plates?

Yes. If the powder is a broth formulation, adding bacteriological agar at about 15 to 20 g per litre before autoclaving gives solid plates for colonies. Check first whether agar is already in the powder, because adding more makes a very firm gel.

How should yeast cultures be disposed of after the practical?

Treat them as microbiological waste: autoclave the plates or broths, or soak them in a suitable disinfectant, before disposal. Baker’s yeast is low risk, but contaminants picked up during the practical may not be.

Last Updated: September 2026