Fermented actives · Coenzyme
A fermentation-derived redox cofactor, supplied as a red-brown crystalline powder at ≥98% assay — in two forms, because the salt you choose decides which formats you can actually make.
Also known as PQQ · pyrroloquinoline quinone disodium salt · methoxatin disodium salt · 4,5-dihydro-4,5-dioxo-1H-pyrrolo[2,3-f]quinoline-2,7,9-tricarboxylic acid disodium salt
Overview
Pyrroloquinoline quinone is a tricyclic quinone that bacteria use as a redox cofactor. Commercially it is not synthesised from scratch: it is produced by fermentation, most commonly with Methylovorus glucosotrophus or Hyphomicrobium denitrificans, then isolated from the broth and crystallised.
The commercial question is rarely “is it PQQ” — it is which PQQ. Two things separate one lot from another, and neither shows up on the label.
First, the salt form. PQQ is sold as the disodium salt and as the free acid. The disodium salt is water-soluble, deep red-brown, and is what capsules, tablets and beverage powders are built on. The free acid is oil-soluble, which is what suspension softgels and oil-based cosmetics need. They are not interchangeable, and a quotation that just says “PQQ” has not answered the question yet.
Second, what the percentage refers to. “98% PQQ” can mean 98% PQQ disodium salt by HPLC, or 98% PQQ content expressed on the anhydrous free-acid basis. Between those two readings sits a factor of about 0.88 — a gap big enough to change your formula and your label. Our certificate states the basis it is calculated on, rather than leaving it to be inferred.
Identity
The identifiers your specification sheet, customs paperwork and product label all have to agree on. Where a number depends on the salt form, both are given.
HS codes are indicative only. Final classification is confirmed per shipment with your customs broker.
Manufacture
Four stages separate the fermentation broth from the lot you receive. Each one leaves a test result on the batch record.
A methylotrophic strain is grown in a two-stage fermentation, and PQQ accumulates in the broth. This is the step that decides whether the material is fermentation-derived at all — a point some suppliers leave unstated, and one your non-GMO or origin declaration may depend on.
Filtration, then resin adsorption and elution. This step removes the bulk of the biomass and the coloured co-metabolites that would otherwise sit in the impurity profile.
pH adjustment and a two-stage crystallisation give the disodium salt; the product is then dried under vacuum and milled. This is where the water content is set, and PQQ holds more of it than most actives.
Assay, identity, water, residual solvent, elemental impurities and microbiological limits are tested against the written specification before the lot is released.
Applications
PQQ is a formulation ingredient, not a finished product. These are the three formats we are asked about most — and the form of PQQ each one needs.
The disodium salt, usually in the low-milligram range per unit. Deep colour and low bulk density mean small-dose blends need a carrier; send the target fill weight and we will quote a milled grade if flow matters more than particle size.
The disodium salt, chosen for solubility. Two constraints are worth testing early: the red-brown colour carries into the finished drink, and PQQ is light- and oxygen-sensitive in solution. Check regulatory ceilings for your market before fixing the dose.
The free acid, not the disodium salt. It disperses in the oil phase; the salt does not. If your formula is a suspension softgel or an anhydrous cosmetic base, specify the acid form at the enquiry stage.
Specification
The written limits we release against, with the method used to test each one. Batch results for the lot you receive are stated on its certificate of analysis.
| Parameter | Limit | Method |
|---|---|---|
| Appearance | Red-brown to deep red-brown crystalline powder | Visual |
| Assay (PQQ disodium salt) | ≥ 98.0% | HPLC-UV |
| Assay basis | Stated on COA: as-is salt, or free-acid equivalent | Calculation |
| Identity | Consistent with reference | LC–MS, ¹H NMR |
| Water content | ≤ 12.0% | Karl Fischer |
| Residual ethanol | ≤ 0.5% | GC |
| Lead | ≤ 1 ppm | ICP-MS |
| Arsenic | ≤ 1.5 ppm | ICP-MS |
| Cadmium | ≤ 0.3 ppm | ICP-MS |
| Mercury | ≤ 0.2 ppm | ICP-MS |
| Total plate count | ≤ 1,000 cfu/g | Plate count |
| Yeast & mould | ≤ 100 cfu/g | Plate count |
| E. coli / Salmonella | Absent | Enrichment |
| Shelf life | 24 months from date of manufacture, unopened | Stability programme |
Tighter limits — for example a lower heavy-metal ceiling or a residual-solvent panel — can be quoted against your own specification wording.
Certificate
Three numbers on this material are routinely misread. If a supplier cannot state them, the “98%” on the label is doing very little work.
A figure on the disodium salt is not a figure on the free acid. Convert with the molecular weights: 374.17 → 330.21, a factor of 0.8825. A lot at 98.0% disodium salt carries roughly 86.5% PQQ on a free-acid basis. Both numbers are correct; only one belongs on your label, and the COA should say which it is reporting.
PQQ disodium salt is hygroscopic, and food-grade specifications commonly allow water up to 12%. That is not a defect — it is the nature of the salt. But it means assay must be read on a stated basis, and it means a lot that has been opened and repacked will drift downward in assay while the chromatogram looks unchanged.
Deep red-brown is inherent to the quinone, so a dark powder is not a bad lot. Two things are worth watching: a shift toward near-black, which usually tracks moisture and oxidation, and a batch noticeably lighter than the previous one, which can indicate a different purity or a different salt. Ask for the reference colour description, not a photograph.
Documentation & packaging
The paperwork travels with the goods. If your QA team needs an extra declaration, ask before the order is released — some are issued per production lot and cannot be retrofitted.
Batch number, assay and its basis, identity, water, residual ethanol, elemental impurities and microbiological results — one page, one lot.
HPLC chromatogram with the integration method stated, plus the mass spectrum used for identity confirmation.
Safety data sheet for handling and transport, and the written specification the batch was released against.
Non-GMO, allergen, TSE/BSE, origin and fermentation-strain statements, issued against the actual production lot — tell us which your market requires.
| Pack size | Presentation | Typical use |
|---|---|---|
| 1–100 g | Amber glass vial, sealed | Evaluation and lab scale |
| 500 g | Nitrogen-flushed foil bag | Pilot batches |
| 1 kg | Foil bag in fibre drum | Commercial |
| 25 kg | Fibre drum, food-grade liner | Bulk — quoted per order |
Questions
The questions buyers actually ask about PQQ. Anything not covered here, ask directly — you will get an answer from someone technical, not a template.
Related
Quotation
Send the quantity, the grade you need and the destination. You will get a written quotation with lead time, packaging options and the documentation set for this material.
