By PathGene Biotech · Technically reviewed by Alex Huang
Sophorolipid HLB and Formulation: Acidic vs Lactonic Forms
Sophorolipid HLB: start with the actual grade
When a formulation brief asks for sophorolipid HLB, a “medium-to-high HLB biosurfactant” or an acidic sophorolipid emulsifier, the useful starting point is the supplied material and its supporting data. PathGene's current sophorolipid listing specifies ≥45% solids content and an 80:20 acid-form:lactone-form ratio. It does not publish a numeric HLB specification. Neither the solids percentage nor that ratio can be converted directly into an HLB number.
For sourcing, use the current sophorolipid product record, which lists CAS 148409-20-5, and confirm the mixture's composition separately. A product identifier alone does not describe every congener, acetylation state or performance property of a commercial mixture.
Acidic and lactonic forms: what changes and what still needs testing
Acidic sophorolipids have an open-chain form with a free carboxyl group; lactonic forms contain an internal ester ring. Commercial materials may contain multiple congeners, with differences in fatty-acid chain and acetylation as well as the acid/lactone balance. The complete composition and the formulation conditions therefore matter when choosing an emulsifier.
Li et al. (2020) compared acidic and lactonic materials at an air-water interface and found that their surface properties changed with concentration and sodium chloride. These measurements do not provide an HLB specification or establish shelf stability in an oil-water formula.
Ma et al. (2022) investigated acidic and lactonic sophorolipids in a particular drug-loaded submicron emulsion. The study supports reviewing oil composition, surfactant concentration and processing together; it does not qualify PathGene's industrial grade for pharmaceutical use or prove that one form is always the better emulsifier.
Read the solids-content and composition evidence separately
| Item | Verified information | Procurement interpretation |
|---|---|---|
| Solids specification | ≥45% | Total solids is not chromatographic chemical purity. |
| Batch PGSL-260121 | 51.3% solids; pH 6.6; produced 21 January 2026 | Actual results for this lot, not identical values guaranteed for future batches. |
| Acid:lactone ratio | 80:20 on the current product listing | The reviewed COA has no ratio result. Request supporting composition analysis and its reporting basis. |
| HLB | No numeric value in the reviewed product documents | Ask how any proposed value was obtained and whether it applies to the supplied mixture. |
| Appearance and storage | Pale yellow to amber transparent liquid; sealed, cool, dry and away from light | Qualify the liquid material and packaging rather than assuming a powder grade. |
The batch COA reports water solubility as compliant. It does not specify a universal solution concentration, CMC, emulsification result or demulsification result. The measured pH of 6.6 and the release specification of 4.0-8.0 belong to the raw-material checks; they do not establish a universally suitable formulation pH.
For the ratio, ask whether the analysis is reported by mass, molar proportion or detector response, and what peaks are included. Request the method, standards, calculation and congener assignment relevant to the offered batch. A method used in a research paper should not be presented as the supplier's routine method without matching documentation.
Formulation checklist for an acidic-rich sophorolipid emulsifier
| Control | Record in the sample evaluation |
|---|---|
| Material and dose | Lot, solids result, composition evidence and whether dosage is measured as supplied liquid or a defined active fraction. |
| Oil/water system | Oil identity, oil/water ratio, intended emulsion type and all co-surfactants or polymers. |
| Aqueous conditions | Measured pH, electrolyte identity/concentration and temperature. |
| Processing | Addition order, mixing/shear conditions, heat exposure and residence time. |
| Performance endpoints | Droplet-size change, visible separation, viscosity and relevant storage observations against controls. |
This is a development checklist rather than a validated recipe. Select concentrations and conditions for the actual application. A stable appearance at one observation point, lower surface tension or stronger foam does not by itself establish long-term emulsion stability.
Emulsification and demulsification need different acceptance criteria
A request to stabilize an emulsion and a request to separate an existing emulsion have different endpoints. For a demulsification project, specify the actual oil/water mixture, residual-oil or residual-water target, dosage, temperature, mixing and settling time. Compare treated and untreated controls. The reviewed PathGene COA establishes raw-material release results; it does not demonstrate a guaranteed demulsification percentage or dosage.
Request the matching sample and bulk documents
Review the sophorolipid specification and batch results alongside the quality and document request process. Provide the intended formulation, target quantity and destination so the offered lot, sample, packaging, MOQ and delivery can be confirmed. Request composition evidence when the acid/lactone ratio is part of your purchase requirement, and qualify performance in your own system.
Frequently Asked Questions
Does sophorolipid have one fixed HLB value?+
The current PathGene grade has no published numeric HLB specification. Confirm the exact congener mixture, measurement or calculation method and formulation conditions before using an HLB classification. The acid-to-lactone ratio alone cannot establish a numeric HLB.
Is an acidic sophorolipid emulsifier always better than a lactonic grade?+
No universal ranking follows from the names. Compare the actual oil phase, concentration, pH, salt conditions, co-surfactants, process and stability endpoints with matched samples. Research findings for one formulation are not a guarantee for another.
Does 45% solids mean 45% pure sophorolipid?+
No. Solids content and chemical purity are different measurements. PathGene batch PGSL-260121 reports 51.3% solids against a ≥45% solids specification; it does not report 51.3% chromatographic sophorolipid purity.
Does the PGSL-260121 COA measure the 80:20 acid-to-lactone ratio?+
The reviewed COA lists solids content, pH and other release items but has no acid-to-lactone ratio result. The current product listing states 80:20; request its supporting composition analysis and reporting basis separately.
Can this grade be specified as a demulsifier without a trial?+
Not from the reviewed batch certificate. Define the separation target and test the actual emulsion, dosage, mixing, temperature and settling time against controls. Record separation and residual oil or water before making a performance specification.
What should I include in a bulk sophorolipid inquiry?+
Provide the target application, oil/water system, required solids basis, desired composition evidence, sample quantity and destination. Request the offered lot COA and confirm packaging, MOQ and delivery for the actual order.
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