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Yeast Peptones and Yeast Extracts

Yeast-based nitrogen sources: peptones keep more peptides, extracts are richer in free amino acids, B-group vitamins and nucleotides. Animal-free, and the most widely used class for lactic acid bacteria, probiotics and general fermentation.

Yeast peptone is produced by enzymatic hydrolysis of yeast protein and consists mainly of short and medium peptides, carrying the B-group vitamins and nucleotides of the yeast itself. Yeast extract is the water-soluble fraction obtained after yeast cells autolyse, with a higher share of free amino acids and flavour nucleotides. Both are animal-free, which suits Halal, vegetarian and animal-origin-free formulations.

In media, yeast-derived nitrogen is often paired with other peptones: the peptone supplies peptides for steady growth, the extract supplies vitamins and growth factors. Lactic acid bacteria, bifidobacteria, bacilli and yeasts all respond well to this class, and standard formulations such as MRS and YPD use yeast extract as a base ingredient.

This page lists the yeast peptones and yeast extracts supplied by STBIO MEDIA. Depending on the product there are clear-solution grades, high B-vitamin, high nucleotide (I+G) and Halal-certified versions; specifications and pack sizes are on each product page.

How to choose

  • Strains that need growth factors (lactic acid bacteria, bifidobacteria and other fastidious organisms): start with yeast extract, or products labelled high B-vitamin.
  • Fermentations that need a steady nitrogen supply: choose yeast peptone, whose peptides release more gradually.
  • Liquid products or cell culture that need clarity: choose a grade labelled clear solution.
  • If you need Halal, non-GMO or animal-free claims: check the certifications and tags on each product page.
  • Undecided: use the peptone selector to filter by organism and requirements, or request a sample for a small-scale trial.
Filter by organism and requirements in the selector

Products in this group

114

Yeast peptones

Mainly short and medium peptides with a steady nitrogen release; the most used in fermentation and probiotics

Yeast–soy complex peptones

Yeast and soy nitrogen in one product, common in actinomycete and Streptomyces fermentation

Cell-culture grade

Ultrafiltered and low in endotoxin for serum-free cell culture

Frequently asked questions

01What is the difference between yeast extract and yeast peptone?

Both come from yeast; the difference is the process and the resulting composition. Extract is the soluble fraction after autolysis, rich in free amino acids, nucleotides and vitamins; peptone is enzymatically hydrolysed protein with a higher share of peptides. Use extract for a fast start, peptone for a steady nitrogen supply, and many formulations use both.

02Do yeast-derived products contain allergens?

Yeast itself is not a regulated major allergen, but some products may declare gluten because of their process or formulation. Refer to the allergen field on each product page and specification sheet.

03Are Halal-certified versions available?

Yes. Products whose code ends in H are Halal-certified; the product page shows a Halal badge and certificate information.

Further reading

Other peptone groups