N-acetyl-β-D-glucosamine

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

26 September 2019 - 24 October 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N-acetyl-β-D-glucosamine

EC Number:

231-368-2

EC Name:

N-acetyl-β-D-glucosamine

Cas Number:

7512-17-6

Molecular formula:

C8H15NO6

IUPAC Name:

N-acetyl-β-D-glucosamine

Test material form:

solid

Specific details on test material used for the study:

Batch number: 0420171228
Provided by Sponsor.
Purity: 99.6%
Stored at room temperature and <70% relative humidity.
Protected from light and humidity in a tightly closed container.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

Secondary effluent, microorganisms from a domestic waste water treatment plant. The secondary effluent was supplied from the sewage plant for domestic sewage in Veszprém county, Hungary. The secondary effluent used for this study was allowed to settle approximately one hour, then the decanted effluent was aerated until use (not later than an hour).

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

>= 4.1 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

- test carried out in an incubator (21-23 C) within a controlled environment room
- oxygen concentration was 8.8 mg/L at start of test. Oxygen measurements performed in duplicate every 7 days from day 0.
- oxygen measurements were taken using an oxygen meter with a stirring O2 electrode.
- Test temperature: 22 +/- 2C, measured on weekdays
- pH: test water 7.27

- BOD flasks were cleaned with 5 - 10 mL of a wash liquid (2.5 g iodine and 12.5 g potassium iodide per litre of 1 % w/v sulphuric acid) by shaking well to coat the bottle walls. Bottles were then rinsed with tap and deionised water.
- test item weighed directly into test vessel.
10 bottles containing the test item and inoculum
10 bottles containing the reference item and inoculum (procedure control) = Sodium benzoate
10 bottles containing only inoculum (inoculum control)
10 bottles containing the test item, reference item and inoculum (toxicity control)

- BOD was calculated by: (mgO2/L or test item and reference item - mg O2/L innoculum control) / (mg test item and reference item in flask)
- Biodegradation % was calculated by: BOD/ ThOD x 100
- ThOD (mg O2/ mg test item or reference item)

- % biodegradation, BOD and oxygen depletion were measured at 7, 14, 21 amd 28 days of exposure
- Dissolved oxygen concentration and oxidised nitrogen were measured at 0, 7, 14, 21, 28 days after exposure

Reference substance

Reference substance:

other: Sodium benzoate

Results and discussion

Preliminary study:

A preliminary study was undertaken and % biodegradation was calculated at 7 and 14 days after exposure for the test item, reference item and toxicity control.

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 76.7

Sampling time:

14 d

% Degradation 2

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 80.1

Sampling time:

28 d

Details on results:

The test item, N-Acetylacetyl-D-gGlucosamine, attained 76.7% biodegradation after 14 days, with 80.1% biodegradation achieved by the end of the 28 day study period. According to OECD Guideline 301D, the pass level for ready biodegradability is 60 % of ThOD within a 10-day window, with a 14-day window also acceptable for closed bottle test.

The reference item sodium benzoate was sufficiently degraded to a mean of 77.5 % after 14 days, and to a mean of 84.2 % after 28 days of incubation (based on ThOD) thus confirming the suitability of the used inoculum.

In the toxicity control containing both the test item N-acetyl-D-glucosamine and the reference item sodium benzoate, a mean of 53.8 % biodegradation was recorded within 14 days and a mean of 55.5 % biodegradation after 28 days of incubation.

Any other information on results incl. tables

Percentage Biodegradation at Different Time Intervals during the Exposure Period of 28 Days

Treatment	Concentration	Flask	Percent of biodegradation after n days of exposure
	[mg/L]	No.	7	14	21	28
Test item		1a	55.6	75.9	76.7	79.2
	4.1	1b	57.5	77.6	76.7	80.9
		mean	56.6	76.7	76.7	80.1
Reference item		2a	74.7	78.3	80.8	85.0
	3.6	2b	70.7	76.7	80.8	83.3
		mean	72.7	77.5	80.8	84.2
Toxicity control	Test item: 4.1 Reference item: 3.6	4a	54.4	54.2	54.6	55.1
		4b	53.5	53.4	55.5	55.9
		mean	53.9	53.8	55.1	55.5

Dissolved Oxygen Concentrations at Different Time Intervals during the Exposure Period of 28 Days

Treatment	Concentration	Flask	mg O2/L after n days of exposure
	[mg/L]	No.	0	7	14	21	28
Test item		1a	8.30	4.72	3.20	3.00	2.80
	4.1	1b	8.40	4.71	3.20	3.10	2.80
		mean	8.350	4.715	3.200	3.050	2.800
Reference item		2a	8.60	3.84	3.30	3.00	2.70
	3.6	2b	8.50	3.98	3.30	2.90	2.70
		mean	8.550	3.910	3.300	2.950	2.700
Inoculum control	–	3a	8.60	8.28	7.90	7.90	7.80
		3b	8.50	8.26	8.00	7.70	7.70
		mean	8.550	8.270	7.950	7.800	7.750
Toxicity control	Test item: 4.1 Reference item: 3.6	4a	8.30	1.50	1.20	1.00	0.90
		4b	8.30	1.61	1.30	0.90	0.80
		mean	8.300	1.555	1.250	0.950	0.850

Oxygen Depletion at Different Time Intervals during the Exposure Period of 28 Days

Treatment	Concentration	Flask	mg O2/L after n days of exposure
	[mg/L]	No.	7	14	21	28
Test item	4.1	1a	3.30	4.50	4.55	4.70
		1b	3.41	4.60	4.55	4.80
Reference item	3.6	2a	4.48	4.70	4.85	5.10
		2b	4.24	4.60	4.85	5.00
Toxicity control	Test item: 4.1 Reference item: 3.6	4a	6.52	6.50	6.55	6.60
		4b	6.41	6.40	6.65	6.70

Total Oxidised Nitrogen at concentrations at Different Time Intervals during the Exposure Period of 28 Days

Treatment	Concentration	Flask	mg total oxidised N per litre after n days of exposure
	[mg/L]	No.	0	7	14	21	28
Test item	4.1	1a	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ
		1b	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ
Inoculum control	–	3a	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ
		3b	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ
Toxicity control	Test item: 4.1 Reference item: 3.6	4a	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ
		4b	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ

LOQ: 4.43 mg NO₃/mL; LOQ: 0.03 mg NO₂/mL;(< LOQ: below the quantification level)

Equipment: Lovibond Maxidirect Photometer using Nitrite LR tablet reagent and Vario NitraX Reagent Set.

BOD at Different Time Intervals during the Exposure Period of 28 Days

Treatment	Concentration	Flask	BOD after n days of exposure
	[mg/L]	No.	7	14	21	28
Test item	4.1	1a	0.80	1.10	1.11	1.15
		1b	0.83	1.12	1.11	1.17
Reference item	3.6	2a	1.24	1.31	1.35	1.42
		2b	1.18	1.28	1.35	1.39
Toxicity control	Test item: 4.1 Reference item: 3.6	4a	0.85	0.84	0.85	0.86
		4b	0.83	0.83	0.86	0.87

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test item, N-Acetylacetyl-D-gGlucosamine, attained 76.7% biodegradation after 14 days, with 80.1% biodegradation achieved by the end of the 28 day study period. According to OECD Guideline 301D, the pass level for ready biodegradability is 60 % of ThOD within a 10-day window, with a 14-day window also acceptable for closed bottle test.

Therefore N-Aacetyl-D-gGlucosamine can be considered to be readily biodegradable.