Hydrogen (glycinato-N,O)[sulphato(2-)-O,O']ferrate(1-)

Endpoint summary

Description of key information

- study conducted prior to implementation of GLP guidelines, biodgradation was measured with a Warburg respirometer, oxidation was measured as percentage of the theoretical oxygen demand, glycine was oxidized to 16.9% of the ThOD, read-across

- study conducted prior to implementation of GLP guidelines, biodgradation was measured by the BOD removal by activated sludge for 10 days in a two day interval, Activated sludge was incubated with 720 mg/L glycine and 86.9% of the BOD was removed after 22 to 24 h, read-across

- study conducted prior to implementation of GLP guidelines, biodgradation was measured the oxidation rate based on the theoretical oxygen demand, Bacillus proteus were incubated with 0.25 mg glycine and pshowed an oxygen uptake of 104 cm³, the oxidation rate was 110 min, read-across

Additional information

Based on the read-across hypothesis that ferrous monoglycinate sulfate in aqueous solutions is readily degraded to glycine and inorganic Fe ions, biodegradability can only be measured for glycine. Glycine is a ubiquitous occurring amino acid which is known to be readily metabolised by all organisms (common books of biochemistry) and the presented publications provide evidence that glycine is readily biodegradable by activated sludge and distinct bacteria.

Data on biodegradation for ferrous monoglycinate sulfate are not available. However, there are several studies providing evidence that glycine as one of the proteinogenic amino acids is readily biodegradable.

In the study of Bernheim (1935) the biodegradation of glycine was determined in Bacillus proteus. The method of determination is considered sufficient, the study was conducted prior to implementation of standard guidelines. Bacillus proteus Type X-2 was grown for 18 hours on beef extract agar slants at 37° and pH 7.4. Subsequently,  a suspension of bacteria  was  used  in  each  Warburg  vessel  and  the  volume  made  up  to  2  cc.  with  buffer  and  a  solution  of  the  amino  acid  to  be  tested. The oxidation rate was measured after 6h. The authors were able to show that glycine in contrast to all other proteinogenic amino acids was fully metabolised by resting Bacillus proteus. Thus, glycine is considered readily biodegradable under the conditions of the test.

In another study of Placak (1947) the biodegradation of glycine was determined via measurement of the BOD. Activated sludge was incubated with 36 pure organic compounds including 720 mg/L glycine. The BOD was measured over 10 days. The results showed that 86.9% of the BOD was removed after 22 to 24h. Thus, glycine is considered to be readily biodegradable under the conditions of the test.

Finally, Malaney (1969) compared the biodegradation of all proteinogenic amino acids. The biological oxygen demand of activated sludge incubated with glycine was determined. Again, this study was conducted prior to implementation of standard guidelines and GLP. The study was reported in sufficient detail and provides evidence that glycine is readily biodegradable. The result reveals that 16.9 % of the compound were degraded within 24 h, therefore glycine is less susceptible to oxidation than the other amino-acids investigated but considered readily biodegradable because it belongs to the same chemical family as the amino acids that are more susceptible to oxidation.

Based on the presented data glycine is considered to be readily biodegradable.