Sophorolipids: fermentation products of glucose and rapeseed-oil fatty acids methyl esters with yeast Candida Bombicola

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 May 2010 to 02 July 2010

Reliability:

1 (reliable without restriction)

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: Inhibition control in Ready Biodegradability Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test organisms (species):

activated sludge of a predominantly domestic sewage

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

28 d

Key result

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

34.7 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: >25% biodegradation (actual 78%) after 14 days in toxicity control

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

54.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: >25% biodegradation (actual 78%) observed in toxicity control after 14 days

Details on results:

The degradation in the toxicity flask was 78% after 14 days. Therefore, it can be considered that the test item is not toxic towards the inoculum at the test concentration of 54.4 mg/L. The test item in the 301B study was reported to have a purity of 63.84%, which reflects that the commercial Sophorolipids product is an aqueous solution. Correcting for this purity, gives an actual test concentration for the sophorolipid content (active ingredient) of 34.73mg/L. This concentration can be considered as a NOEC for the toxicity to STP microorganisms.

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of Sophorolipids to microorganisms was assessed in an inhibition control of a standardised ready test performed according to OECD 301B. Sophorolipids did not inhibit the degradation of the positive control, aniline, at a test concentration of 54.4mg/L (test material, 63.84% purity) or 34.73 mg/L (active ingredient, Sophorolipid content). The latter concentration can be considered the NOEC for the toxicity to STP microorganisms.

Description of key information

In a ready biodegradability screening study (OECD 301B, key study for the biodegradation endpoint in this dossier), Sophorolipids was found to be readily biodegradable and no toxicity was observed in an inhibition control at a test concentration of 54.4 mg/L. The test item in the 301B study was reported to have a purity of 63.84%, which reflects that the commercial Sophorolipids product is an aqueous solution. Correcting for this purity, gives an actual test concentration for the sophorolipid content (active ingredient) of 34.7mg/L. This concentration can be considered as a NOEC for the toxicity to STP microorganisms.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

34.7 mg/L