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

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Water solubility:

> 879 g/L

Temp.:

20 °C

pH:

>= 4.07 - <= 4.12

Details on results:

A preliminary test indicated that the solubility of the water solubility of the test item was higher than 500 g/L at 20 °C. Due to this high solubility, a lower limit definitive test was performed to show that the water solubility of Sopholiance S was higher than about 800 g/L. Five constituents of the test item were quantified: Lactone A, lactone A’, Sophorolipid B, Sophorolipid C and Sophorolipid D. There was no significant change of the measured concentrations after 24, 48 and 72h. Thus the results obtained after 24, 48 and 72h were averaged to give mean measured concentrations of 135g/L (Lactone A), 17.9g/L (Lactone A’), 211 g/L (Sophorolipid B) 124 g/L (Sophorolipid C) and 43.2g/L (Sophorolipid D). Dividing this value by the known % w/w of each constituent in Sopholiance S resulted in water solubility values of 894, 886, 879, 886 and 896 g/L respectively, thus confirming that each constituent was fully solubilised. From the results of this test it was concluded that the solubility of Sopholiance S in water is higher than 879 g/L at 20 ± 1°C.

Hydrosolubility results

Test solution	Lactone A mean concentration (g/L)	Lactone A’ mean concentration (g/L)	Sophorolipid B mean concentration (g/L)	Sophorolipid C mean concentration (g/L)	Sophorolipid D mean concentration (g/L)
After 24 h A1(pH = 4.12) B1(pH = 4.08)	135 128	18.5 16.8	215 206	127 118	43.7 40.6
After 48 h A2(pH = 4.09) B2(pH = 4.07)	132 133	17.4 17.7	201 215	126 124	43.3 43.4
After 72 h A3(pH = 4.07) B3(pH = 4.10)	140 139	18.5 18.2	215 211	127 122	44.4 44.0
Mean concentration   RSD (%)	135   3.3	17.9   3.8	211   2.8	124   2.8	43.2   3.1
% w/w sophorolipid in Sophorolipids water solution*	15.1	2.02	24.0	14.0	4.82
Hydrosolubility of Sophorolipids	894	886	879	886	896

Conclusions:

The solubility of Sopholiance S in water is higher than 879 g/L at 20 ± 1°C.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Key result

Water solubility:

1 000 g/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

7

Details on results:

A preliminary test was performed at 1000g/L. A sample of 1g of Freeze dried Sopholiance was dissolved in 1.00ml of ultrapure water. After 1h of mixing a visibly clear homogenous solution was obtained. As the results of the preliminary test were conclusive, a main test was not conducted. From the results of the preliminary test it was concluded that the solubility of Freeze dried Sopholiance in water at 20 °C is ≥ 1000 g/l.

Conclusions:

The solubility of Freeze dried Sopholiance in ultrapure water was determined in a
preliminary test as described in the OECD Guideline No. 105.
The result is:
Solubility in water: 1000 g/l at 20°C
This result corresponds to the saturation mass concentration of Freeze dried
Sopholiance in ultrapure water at 20°C.

Description of key information

The water solubility of the registered substance has been determined at 20.0°C in two independent tests. Both studies were performed according to OECD guideline No 105, using the shake flask method.  It was concluded that the water solubility of the registered substance was > 879 g/L (Processium 2012, support study, non-GLP) and ≥ 1000 g/L (Dutriez 2019, key study, GLP). The highest value has been selected as the key value.

Key value for chemical safety assessment

Water solubility:

1 000 g/L

at the temperature of:

20 °C

Additional information

In the first study (Processium 2012), a preliminary test indicated that the solubility of  the water solubility of the test item was higher than 500 g/L at 20 °C. Due to this high solubility, a lower limit definitive test was performed to show that the hydrosolubility of Sopholiance S was higher than about 800 g/L. Five constituents of the test item were quantified: Lactone A, lactone A’, Sophorolipid B, Sophorolipid C and Sophorolipid D. There was no significant change of the measured concentrations after 24, 48 and 72h. Thus the results obtained after 24, 48 and 72h were averaged to give mean measured concentrations of 135g/L (Lactone A), 17.9g/L (Lactone A’), 211 g/L (Sophorolipid B) 124 g/L (Sophorolipid C) and 43.2g/L (Sophorolipid D). Dividing this value by the known % w/w of each constituent in Sopholiance S resulted in water solubility values of 894, 886, 879, 886 and 896 g/L respectively, thus confirming that each constituent was fully solubilised. From the results of this test it was concluded that the solubility of Sopholiance S in water is higher than 879 g/L at 20 ± 1°C.

In the second study (Dutriez 2019), a preliminary test was performed at 1000g/L. A sample of 1g of Freeze dried Sopholiance was dissolved in 1.00ml of ultrapure water. After 1h of mixing a visibly clear homogenous solution was obtained. As the results of the preliminary test were conclusive, a main test was not conducted. From the results of the preliminary test it was concluded that the solubility of Freeze dried Sopholiance in water at 20 °C is ≥ 1000 g/L.