One of the things fermentation engineers fear most in scale-up is a medium that performs in the small tank and behaves differently in the large one. The nitrogen source is the most variable component: batch-to-batch variation, solubility, foaming and pH buffering are all amplified with volume. So when a published patent uses the same yeast peptone from 3 L through to 500 L in its examples, it is a document worth reading.
What the patent discloses
US Patent 11,833,116 B2 (granted 2023, applicant TCI Co., Ltd.) concerns the preparation of yeast powder rich in NMN (nicotinamide mononucleotide). The basal medium of Example 1 is as follows, with percentages as stated in the patent:
| Component | Amount |
|---|---|
| Yeast Peptone GLS (manufacturer: STBIO MEDIA, INC.) | 2.0% |
| Yeast extract 902 | 2.0% |
| Potassium dihydrogen phosphate | 0.5% |
| Dipotassium hydrogen phosphate | 0.5% |
| Magnesium sulfate | 0.05% |
| Glucose | 10% |
| Citric acid | 0.17% |
Each stage's fermentation medium additionally contains 0.1% nicotinamide, 0.2% tryptophan and 0.0369% niacin as precursors for NMN synthesis.
The three culture stages are 3 L, 50 L and 500 L, all on the same basal medium. The authoritative text is the Google Patents record, linked from our publications page.
What it tells you about scale-up
The interesting part is not NMN itself but a few engineering details.
The nitrogen source is unchanged across three orders of magnitude. The same yeast peptone is used from 3 L to 500 L, meaning the applicant did not reformulate the nitrogen source between seed and production stages. For purchasing and process teams this is the most direct kind of evidence that one product can run from laboratory pack to industrial pack; Yeast Peptone GLS (Ref. 26891H) is itself supplied from 500 g to 25 kg.
Peptone and extract are used together. 2.0% peptone with 2.0% yeast extract is a common pairing in yeast fermentation: the peptone supplies peptides for steady biomass growth, the extract supplies vitamins and growth factors. The ratio varies by process, but two yeast-derived nitrogen sources side by side is the starting point of many high-density cultures.
The carbon-to-nitrogen ratio is high. 10% glucose against 4% nitrogen sources is a formulation aimed at product accumulation rather than biomass. On scale-up the carbon feeding strategy usually needs more adjustment than the nitrogen source, which is also why the nitrogen can stay the same across three stages while carbon needs staged design.
What it cannot be used for
A patent example is an experiment the applicant ran to describe the invention. It is not a recommendation from the medium manufacturer, nor an independent verification of product performance. Three lines to hold when reading this kind of literature:
- A patent naming our product does not mean the applicant currently purchases it, nor that the process has been commercialised. 500 L is the scale of the example, not a plant capacity.
- The percentages were designed for that strain and that product; with a different strain or product, the nitrogen dose has to be retested.
- Conditions the example does not disclose (dissolved oxygen, agitation, feeding) all affect the outcome. Preparing the medium from the table alone will not reproduce the yield.
The right way to use this document in your own process is as a starting point: run a set at a similar C:N ratio in shake flasks or a small tank, confirm how the nitrogen source behaves on your strain, then scale.
Other patents naming our products
Beyond this one, two further published patents name our products in their examples: one cultures Bifidobacterium breve in a 5 L fermenter on food-grade MRS Broth, the other cultures a Rhizopus microsporus strain on Potato Dextrose Broth to make a fermented food. All three are listed in the patent section of our publications page, alongside the peer-reviewed papers whose methods sections name our products.
Related products
- Yeast Peptone GLS (Ref. 26891H): the yeast peptone used in the patent examples.
- Lactobacilli MRS Broth Food Grade (Ref. 21168H): the food-grade MRS Broth used in the second patent.
- Yeast peptones: compare other yeast peptones by amino nitrogen, solubility and use.
To choose a nitrogen source for your own fermentation, start with choosing a nitrogen source for fermentation, or request a sample and compare in a small tank.