Soy milk keeps contaminating your fermenter? Replace it with soy peptone and ISP
A stable, sterile, traceable plant nitrogen source in place of in-house soy milk
THE SITUATION AND THE PAIN POINTS
Many fermentation plants use in-house soy milk as the nitrogen source. It is nutritious, but protein content varies from batch to batch of beans, and grinding and storage readily introduce contaminants that spoil the fermenter; preparing and chilling large volumes costs labour and energy, and one contamination event loses the whole batch and days of capacity. Other plants switch to commercial soy protein isolate (ISP/SPI) and find that, being made for food use, it dissolves poorly in a fermenter: sediment remains after stirring, lumps stick to the vessel wall, and less nitrogen reaches the broth than the label suggests, so the dose keeps creeping up.
OUR APPROACH
STBIO's soy protein powders (the Soy Protein Powder range) are designed around both problems: soy protein given a controlled enzymatic treatment for better solubility and dispersion, dissolved and sterilised with the medium so it brings in no additional flora; a dry powder stored at room temperature and ready to use, with total and amino nitrogen specified and a COA for every batch. Nitrogen is released gradually, which suits long fermentations and high-cell-density culture. For a fast start, pair it with soy peptone, already hydrolysed into peptides and amino acids. Food-grade, non-GMO and animal-free.
- Specified total and amino nitrogen with a COA for every batch, independent of bean quality
- Dry powder stored at room temperature; no grinding, filtering, or chilling
- Sterilised with the medium, eliminating contamination introduced during soy milk preparation
- Plant-derived and non-GMO, suitable for Halal and vegetarian-labelled products
- Replaces conventional ISP: better solubility and dispersion, no sediment or wall fouling, so the nitrogen actually reaches the broth
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Frequently asked questions
01How do I convert the dosage when switching from soy milk?
Convert on a nitrogen basis. Work out the total nitrogen your soy milk recipe delivered, then convert it to grams using the total-nitrogen percentage on the peptone specification sheet. The powder dosage is usually far lower than the soy milk solids. We can help calculate a starting dose from your recipe.
02How does STBIO soy protein powder differ from ordinary ISP?
Ordinary ISP is a purified protein made for food; in a fermenter it lumps and settles, and the strain has to break it down with its own proteases. STBIO's Soy Protein Powder range is designed for fermentation: a controlled enzymatic treatment improves solubility and dispersion, and nitrogen is released gradually, suiting long fermentations and high-cell-density culture. For a fast start, pair it with hydrolysed soy peptone; the two are often used together.
03Will it change the flavour or colour of the final product?
Peptone solutions are lighter in colour and more neutral in flavour than soy milk; most customers report a more consistent product colour after switching. If your product depends on a particular soy note, run a small trial first.