Biodegradability
- Also known as
- readily biodegradable, inherently biodegradable, biodegradable
Biodegradability is the ability of a substance to be broken down by microorganisms into simpler substances such as carbon dioxide, water and biomass. For chemicals, it is measured by standardized tests that classify a substance as readily biodegradable, inherently biodegradable or persistent.
What is biodegradability?
Biodegradability describes whether, and how quickly, microorganisms such as bacteria and fungi can break a substance down. Complete breakdown, called ultimate biodegradation, converts an organic chemical into carbon dioxide, water, mineral salts and new microbial biomass. Partial breakdown, called primary biodegradation, alters the original molecule but may leave intermediate products behind.
For ingredients such as surfactants, biodegradability matters because many products end up in wastewater or directly in the environment after use.
Categories of biodegradability
Regulators and ingredient standards commonly use three categories, based on standardized laboratory tests:
| Category | What it means | Typical test |
|---|---|---|
| Readily biodegradable | Breaks down rapidly and extensively under stringent test conditions | OECD 301 series |
| Inherently biodegradable | Can biodegrade, but only under more favorable conditions or over longer periods | OECD 302 series |
| Not biodegradable, or persistent | Does not break down significantly in tests | Fails both |
“Readily biodegradable” is a demanding, specific result, not a general claim: under OECD 301, a substance must reach a set level of breakdown within 28 days, and do so quickly once degradation begins.
What affects biodegradation
- Molecular structure. Linear chains, ester bonds and natural building blocks, such as sugars and fatty acids, tend to biodegrade readily; highly branched, fluorinated or aromatic structures often do not.
- Conditions. Oxygen, temperature, the microbial community and the concentration of the substance all affect the rate. Aerobic and anaerobic tests give different results.
- Toxicity. A substance that is toxic to microorganisms at the test concentration can appear not to biodegrade.
Biodegradability and product claims
Because a substance’s biodegradability depends on its structure and the test used, reliable claims name the test and result, for example “readily biodegradable per OECD 301B.” Ingredient standards such as EPA Safer Choice set biodegradation criteria for surfactants, and stricter ones for direct release products used where they enter the environment without wastewater treatment. Aquatic toxicity is usually assessed alongside biodegradability.
Biodegradability and Locus biosurfactants
Locus describes its Amphi glycolipid biosurfactants as readily biodegradable and lists biodegradability among the product properties it publishes.
Frequently asked questions
It means a substance passed a stringent ready biodegradability test, such as one of the OECD 301 methods, by reaching the required level of breakdown within 28 days. It indicates that the substance is expected to break down rapidly in the environment.
No. Biobased content describes where the carbon in a product comes from. Biodegradability describes what happens to it after use. A biobased material can be persistent, and a petroleum-derived material can be readily biodegradable.
Sources
- OECD Test No. 301: Ready Biodegradability, Organisation for Economic Co-operation and Development
- OECD Test No. 302: Inherent Biodegradability, Organisation for Economic Co-operation and Development