Catalase

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:

05 August 2010 to 07 October 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to the OECD Guideline but is not in compliance with GLP.

Justification for type of information:

Biodegradability studies according to OECD 301 test guidelines have been performed with a wide variety of industrial enzymes. The physico-chemical properties of enzymes including logKow are very similar. They are proteins built up of amino acids and the type, order and number of the amino acids in the polymer differs between enzymes, determining the 3-dimensional structure, the activity and specificity of the individual enzyme type. Because all enzymes are built up of the same amino acids, the physical and chemical characteristics will be very similar for different enzymes. Therefore, industrial enzymes belonging to other enzyme classes were generally found to be readily biodegradable. Similarly, although the biodegradation study with catalase wasn’t conducted GLP, catalase was also found to be readily biodegradable. The weight-of-evidence indicates that enzymes in general are readily biodegradable.

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

no

Remarks:

.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Duration of test (contact time):

28 d

Initial conc.:

5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

other: dissolved oxygen

Details on study design:

Test Medium Preparation: BOD nutrients were added at the rate of 1 mL each/L deionized water. Inoculum (15 mL) was added to 15 L of mineral medium. The test medium was aerated for approximately 20 minutes.

Preparation of Blank Solution: Mineral media (3.5 L) was used as a blank, and homogenized for approximately 40 minutes.

Preparation of Test Substance Solution (5 mg/L): The test substance (17.6 mg) was added to 3.5 L of test medium, and homogenized for approximately 30 minutes.

Preparation of Reference Solution: Distilled aniline (7.1 mg) was added to 3.5 L of test medium, and homogenized for approximately 30 minutes.

Preparation of Toxicity Reference Solution: 6.9 mg of distilled aniline and 17.8 mg of the test substance were added to 3.5 L of test medium, and homogenized for approximately 35 minutes.

BOD Bottles: Each solution was siphoned from the lowest quarter (not the bottom) of prepared solution container and transferred to labeled BOD bottles. The day 0 samples were examined for dissolved oxygen and the remaining bottles were to be stored in the dark and incubated at 21 °C.

Sampling Intervals: Two BOD bottles for each solution were removed at each sampling interval (0, 7, 14, and 28 days). The oxygen in each duplicate set of solutions was measured and recorded at each interval.

Reference substance:

aniline

Key result

Parameter:

% degradation (test mat. analysis)

Value:

64.6

Sampling time:

28 d

Parameter:

COD

Value:

0.14 mg O2/g test mat.

Results with reference substance:

A value of 67.4% biodegradation was obtained on Day 14 for distilled aniline.

Table 1: Dissolved Oxygen Measurements

Test Group	Day0 DO (mg/L)	Day7 DO (mg/L)	Day14 DO (mg/L)	Day 28 DO (mg/L)
Blank	8.18	7.83	7.71	7.55
	8.19	7.88	7.77	7.46
Test Substance	8.41	7.88	7.56	7.19
	8.42	7.88	7.60	7.37
Distilled Aniline	8.30	7.01	4.50	4.16
	8.25	7.57	4.59	4.16
Toxicity Reference	8.36	5.14	4.36	*measurements did not take place
	8.39	5.05	4.21

 

           

Table 2: Biodegradation Calculations:

	Day 7 calculations	Day 14 calculations	Day 28 calculations
Blank Depletion (mgIL)	0.33	0.445	0.68
Distilled Aniline Net D.O. Depletion (mg/L)	0.655	3.285	3.435
Distilled Aniline ThOD (mg02/mg)	2.405
Distilled Aniline Dose (mg/L)	2.028
Distilled Aniline Calculated % degradation	13.4%	67.4%	70.4%
Test Substance Net D.O. Depletion (mg/L)	0.205	0.39	0.455
Test Substance COD (mgO2/mg)	0.14
Test Substance Dose (mg/L)	5.03
Test Substance Calculated % Degradation	29.1%	55.4%	64.6%

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Under the study conditions, Catalase is considered to be readily biodegradable.

Executive summary:

The study was conducted to measure the biodegradability of Catalase according to the OECD Guideline 301-D in an aerobic, aqueous medium at a concentration of approximately 5 mg/L of active material.

The solutions were prepared using deionized water with activated sludge. The solutions were kept in closed bottles in the dark at 21°C. The degradation was measured by dissolved oxygen analyses over a 28-day period. A standard reagent of known performance (distilled aniline) and a blank were tested at the same time to serve as a control for biological activity.

Under the condition of the study, maximum means of 29.1 %, 55.4% and 64.6% biodegradation were obtained for the test substance on Days 7, 14, and 28, respectively. Therefore, the test substance is considered to be readily biodegradable.

Description of key information

Catalase was found to be readily biodegradable in the OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The study was conducted to measure the biodegradability of Catalase according to the OECD Guideline 301-D in an aerobic, aqueous medium at a concentration of approximately 5 mg/L of active material. The solutions were prepared using deionized water with activated sludge. The solutions were kept in closed bottles in the dark at 21°C. The degradation was measured by dissolved oxygen analyses over a 28-day period. A standard reagent of known performance (distilled aniline) and a blank were tested at the same time to serve as a control for biological activity. Under the condition of the study, maximum means of 29.1 %, 55.4% and 64.6% biodegradation were obtained for the test substance on Days 7, 14, and 28, respectively. Therefore, the test substance is considered to be readily biodegradable.