Kombucha

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2022

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

yes

Remarks:

Temperature range was 18.3 – 21.6 °C instead of 22 ± 2 °C. As degradation of the positive control was in the normal range this is considered as uncritical concerning the outcome of the study.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Fermentation product of sucrose and Theaceae Camellia Camellia sinensis leaves with a variable symbiosis of bacteria and yeast, of including bacteria of Acetoacteraceæ Acetobacter and Gluconobacter genus, and yeasts of Saccharomycetaceae family

Molecular formula:

Not applicable

IUPAC Name:

Fermentation product of sucrose and Theaceae Camellia Camellia sinensis leaves with a variable symbiosis of bacteria and yeast, of including bacteria of Acetoacteraceæ Acetobacter and Gluconobacter genus, and yeasts of Saccharomycetaceae family

Test material form:

liquid

Details on test material:

- Synthesis batch: KOMBUCHA R_001
- CAS no. : 100085-62-9
- Production date: 2021-10-11
- Expiry date: 2022-10-03
- Stability : stable under storage conditions
- Appearance : clear, dark yellow to orange liquid
- Storage in Test Facility: -15 to -25°C

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Inoculum concentration: 25.0 mg/L
Temperature 18.3 – 21.6 °C without direct lighting

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

20 mg/L

Details on study design:

The test item in a mineral medium was inoculated and incubated under aerobic conditions in the dark. The amount of organic carbon in the test solution due to the inoculum was kept as low as possible compared with the amount of organic carbon due to the test item. Allowance was made for the endogenous activity of the inoculum by running parallel blanks with inoculum but without test item. A positive control was run in parallel to check the operation of the procedures. Degradation was followed by determining the carbon dioxide produced. Measurements were taken at sufficiently frequent intervals to allow the identification of the beginning and end of biodegradation.

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (test mat. analysis)

Value:

18.6

Sampling time:

2 d

% Degradation 2

Parameter:

% degradation (inorg. C analysis)

Value:

45.4

Sampling time:

4 d

% Degradation 3

Parameter:

% degradation (inorg. C analysis)

Value:

57.7

Sampling time:

7 d

% Degradation 4

Parameter:

% degradation (inorg. C analysis)

Value:

65.6

Sampling time:

9 d

% Degradation 5

Parameter:

% degradation (inorg. C analysis)

Value:

67.7

Sampling time:

11 d

% Degradation 6

Parameter:

% degradation (test mat. analysis)

Value:

72.4

Sampling time:

14 d

% Degradation 7

Parameter:

% degradation (inorg. C analysis)

Value:

72.6

Sampling time:

18 d

% Degradation 8

Parameter:

% degradation (inorg. C analysis)

Value:

77.8

Sampling time:

23 d

% Degradation 9

Parameter:

% degradation (test mat. analysis)

Value:

78.8

Sampling time:

29 d

Details on results:

The test item Kombucha;Echa name: "Fermentation product of sucrose and Camellia sinensis (Theaceae) leaves with a variable symbiosis of bacteria and yeast, including various Acetoacteraceæ bacteria and Saccharomycetaceae yeasts" is considered as “readily biodegradable“.

The degree of biodegradation reached 79 % after 28 days.

The 10-day-window began on day 1, at its end, 68 % degradation were reached, surpassing
the pass level of 60 % given in the OECD guideline.

Because the test item is a mixture, the 10-day window has not to be taken into account.
As degradation reached the pass level of 60% in the course of the test, Kombucha;Echa name: "Fermentation product of sucrose and Camellia sinensis (Theaceae) leaves with a variable symbiosis of bacteria and yeast, including various Acetoacteraceæ bacteria and Saccharomycetaceae yeasts" is considered as readily biodegradable, within 28 days.

The abiotic degradation reached 0.7 %.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

As degradation reached the pass level of 60% in the course of the test, Kombucha;Echa name: "Fermentation product of sucrose and Camellia sinensis (Theaceae) leaves with a variable symbiosis of bacteria and yeast, including various Acetoacteraceæ bacteria and Saccharomycetaceae yeasts" is considered as readily biodegradable, within 28 days.

Executive summary:

The test item Kombucha; Echa name: "Fermentation product of sucrose and Camellia sinensis (Theaceae) leaves with a variable symbiosis of bacteria and yeast, including various Acetoacteraceæ bacteria and Saccharomycetaceae yeasts" was tested using a concentration of nominally 20 mg organic carbon/L Kombucha;Echa name: "Fermentation product of sucrose and Camellia sinensis (Theaceae) leaves with a variable symbiosis of bacteria and yeast, including various Acetoacteraceæ bacteria and Saccharomycetaceae yeasts" in test medium following OECD 301B and EU-Method C.4-C.

Aniline was chosen as positive control.
Activated sludge was used as inoculum (concentration in the test 25.0 mg dry matter/L). The test was left running for 28 days.
All validity criteria were met. Degradation of the positive control surpassed the pass level of 60 % after 7 days.

The following data were determined for the test item Kombucha;Echa name: "Fermentation product of sucrose and Camellia sinensis (Theaceae) leaves with a variable symbiosis of bacteria and yeast, including various Acetoacteraceæ bacteria and Saccharomycetaceae yeasts":

10-day-window: day 1 – 11

- degradation at the end of 10-day-window 68 %

- degradation at the end of the test 79 %

- pass level following guideline: 60 % at the end of 10-day-window for pure substances; respective 60 % at the end of the test for mixtures

Therefore, when applying the 10-day-window, Kombucha;Echa name: "Fermentation product of sucrose and Camellia sinensis (Theaceae) leaves with a variable symbiosis of bacteria and yeast, including various Acetoacteraceæ bacteria and Saccharomycetaceae yeasts" is readily biodegradable following OECD 301B and EU C.4-C respectively.

Because the test item is a mixture the 10-day-window does not have to be taken into account. As degradation reached the pass level of 60% in the course of the test, Kombucha;Echa name: "Fermentation product of sucrose and Camellia sinensis (Theaceae) leaves with a variable symbiosis of bacteria and yeast, including various Acetoacteraceæ bacteria and Saccharomycetaceae yeasts" is considered as readily biodegradable, within 28 days.