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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Biodegradation study of test substance4-Amino-1,1’-azobenzene-3,4'-disulfonic acid (acid yellow 9) was performed using 15 different Streptomyces spp. for 14 days. The test was performed using 15 different Streptomyces sppas an inoculum. The test substance conc. used is 50 mg/l. 

Each Streptomyces spp. was grown in a cotton-plugged 250 ml flask containing 25 ml of the following medium: 0.2 M Tris buffer (pH 7.6) 100 ml, 1.0g vitamin-free Casamino acids, 100 µg thiamine, 100 µg biotin, 2 g D-glucose, 900 ml deionized wate. Thiamine, biotin, and D-glucose were filter sterilized and added to the autoclaved medium. The dye was filter sterilized and added at 0.005% (w/v) to the autoclaved basal medium. Cultures were incubated at 37ᵒC for 14 days with shaking (200 rev min1). Three replicates for each strain grown in only the basal medium were incubated as well. Degradation of test substance was determined by spectrophotometrically and by using HPLC. The percentage biodegradation of test substance was found to be 0% i.e; no degradation of test substance was observed by the 15 different Streptomyces spp. Thus, the test substance was found to be non-biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

A number of studies and predicted data for the test compound4-Aminoazobenzene-3,4'-disulfonic acid (CAS no. 101-50-8)and its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

Biodegradation study (A. Paszcyzynski et. al: 1991) of test substance4-Amino-1,1’-azobenzene-3,4'-disulfonic acid (acid yellow 9) was performed using 15 differentStreptomyces spp. for 14 days.The test was performed using 15 differentStreptomyces spp as an inoculum. The test substance conc. used is 50 mg/l.

EachStreptomyces spp. was grown in a cotton-plugged 250 ml flask containing 25 ml of the following medium: 0.2 M Tris buffer (pH 7.6) 100 ml, 1.0g vitamin-free Casamino acids, 100 µg thiamine, 100 µg biotin, 2 g D-glucose, 900 ml deionized wate. Thiamine, biotin, and D-glucose were filter sterilized and added to the autoclaved medium. The dye was filter sterilized and added at 0.005% (w/v) to the autoclaved basal medium. Cultures were incubated at 37ᵒC for 14 days with shaking (200 rev min1). Three replicates for each strain grown in only the basal medium were incubated as well.Degradation of test substance was determined by spectrophotometrically and by using HPLC.Degradation of the test substance was confirmed by HPLC. A Hewlett-Packard HP 1090 Liquid Chromatograph equipped with a HP 40 diode array UV-VIS detector and automatic injector was used. The chromatograph was controlled by an HP 9000 series 300 computer which used HP 7995 A ChemStation software. A reverse phase column from Phenomenex (Rancho Palos Verdes, CA, type Spherex 5C 18 size 250 × 2.0 mm, s/no PP/6474A) was used. Each 15-min analysis used a solvent gradient of acetonitrile (solvent A) and 10mM DMS buffer pH 4.5 (solvent B), with the following conditions: 0-5 min, 100% A; 5-12 min, 25% A, 75% B; 12-15 min, 100% B; post time 2 min, injection volume 10µl. Absorption was measured at 250, 325, 350, 400 and 450 nm, and spectra were collected automatically by the peak controller.Spectrophotometric assay was also carried out. A 1 ml sample of actinomycete culture medium was centrifuged and then diluted 2.5 fold with water. Azo dye substrate present was then measured spectrophotometrically (Hewlett-Packard 8452 diode array spectrophotometer operated by PC Vectra computer with HP’s MSTM-DOS/UV-VIS software).The percentage biodegradation of test substance was found to be 0% i.e; no degradation of test substance was observed by the 15 differentStreptomyces spp. Thus, the test substance was found to be non-biodegradable.

 

 

 

Estimation Programs Interface Suite (EPI suite) was run to predict the biodegradation potential of the test compound 4-Aminoazobenzene-3,4'-disulfonic acid (CAS no. 101-50-8). The screening test inherent to the biodegradability of the substance was calculated using the software BIOWIN v4.10. The results indicate that4-Aminoazobenzene-3,4'-disulfonic acidis not expected to be readily biodegradable.

 

 

 

The aim of the study was to estimate the microbial decomposition of Food yellow 4 dye (Yasuhide TONOGAI et. al; 1978). The biodegradation of chemical was determined by 3 methods under aerobic conditions: Aerobic decomposition of dyes with sludge, Oxygen uptake and BOD determination. During 10 days of the aerobic experiment, the absorbance of dye solution was measured once day for 10 days. 20% decomposition of test chemical was obtained in10 days. 3.82 O2 mg/hg – sludge oxygen uptake was obtained in 5 –hrs test and the dissolved oxygen contents on the 5th day were essentially the same to initial ones. The low reactivity of aerobic sludge towards dyes was confirmed. Based on the results obtained from the aerobic degradation assay , Warburg method and BOD determination it can be concluded that tartrazine is not readily biodegradable under aerobic conditions.

 

 

The biodegradation study of test chemical Disodium 2-amino-5-[(4-sulphonatophenyl)azo] benzenesulphonate was performed for 28 days according to the OECD TG 302B (GSBL, 2016). Activated sludge was used as an inoculum. Parameter used for the biodegradation study was DOC removal. After 28 days, no degradation of test chemical Disodium 2-amino-5-[(4-sulphonatophenyl)azo]benzenesulphonate was observed. Thus, the test substance was found to be non-biodegradable.

 

On the basis of the overall reported results of target and its read across substance, it can be concluded that the substance was found to be not-readily biodegradable.