D-cellobiose

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Nov to Dec 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

yes

Specific details on test material used for the study:

Lot: L1018031

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Mixed microbial population from the municipal wastewater treatment plant Jena-Zwätzen First stage effluents, sampling date: 2019-11-19
Activated sludge, sampling date: 2019-11-19 (TSS concentration: 6,1 g/l)
The activated sludge was aerated at 22 °C until use to reduce endogenous respiration. Just prior to use, the sludge was centrifuged twice. The supernatant was discarded and the sediment was resuspended in distilled water. The first stage effluent was aerated at 22 °C until use.

Duration of test (contact time):

28 d

Initial conc.:

ca. 118 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

The vessels contained 250 ml of the inoculated buffered mineral salt medium and the test material (test substance or reference substance) as the sole carbon source. To each test series blanks (without test material) were set up to run in parallel. Incubation was conducted at 22 ± 1° C in diffuse light and agitation by magnetic stirrers. All analyses were conducted at least in duplicate.

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 66

St. dev.:

1

Sampling time:

12 d

Remarks on result:

other: Day 12 was the end of the 10-day window.

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 86

St. dev.:

1.7

Sampling time:

28 d

Results with reference substance:

91% biodegradation within 14 days

		biodegradation (%)
		test sample			reference
date	day	no. 1	no. 2	no. 3	no. 1	no. 2
21.11.19	0	0	0	0	0	0
	1	2,8	1	4,5	30	33
	2	21	18	22	42	40
	3	33	31	35	54	55
	4	42	40	44	67	70
	5	49	47	50	74	80
	6	54	53	55	79	83
	7	56	55	57	79	84
	8	59	59	60	81	84
	9	63	61	63	83	86
	10	63	62	65	85	88
	11	65	64	66	88	89
	12	66	65	67	89	91
	13	67	67	69	89	92
	14	67	67	70	90	93
	15	68	68	70	90	93
	16	69	70	72	90	94
	17	71	72	75	92	96
	18	73	74	77	92	96
	19	74	75	78	92	97
	20	75	77	80	92	97
	21	77	79	81	92	96
	22	79	81	83	92	97
	23	81	83	84	92	97
	24	81	84	85	93	98
	25	83	85	86	93	98
	26	83	86	87	93	98
	27	83	87	87	93	98
19.12.19	28	84	87	87	93	98

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

In a valid study according to OECD TG 301F (manometric respirometry test), cellobiose degraded to 86% within 28 days.
The 10-day-window of biodegradation began on day 2. At its end (day 12), 66 % biodegradation was reached, which is greater than the pass level of 60% given in the guideline . Therefore, cellobiose is considered to be readily biodegradable.

Executive summary:

In a valid study according to OECD TG 301F (manometric respirometry test), cellobiose degraded to 86% within 28 days.
The 10-day-window of biodegradation began on day 2. At its end (day 12), 66 % biodegradation was reached, which is greater than the pass level of 60% given in the guideline . Therefore, cellobiose is considered to be readily biodegradable.

Description of key information

In a valid study according to OECD TG 301F (manometric respirometry test), cellobiose degraded to 86% within 28 days.
The 10-day-window of biodegradation began on day 2. At its end (day 12), 66 % biodegradation was reached, which is greater than the pass level of 60% given in the guideline . Therefore, cellobiose is considered to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater