Zinc glycinate sulfate

Endpoint summary

Description of key information

Data on biodegradation of zinc monoglycinate sulfate are not available. However, since the test item consists of glycine and the inorganic zinc and sulfate ion, only data on the biodegradation of glycine is provided. Several published studies provide evidence that glycine is readily biodegradable. Moreover, glycine is present in virtually every living organism and it is an integral part of the interediary metabolism and can be used as carbon source for energy supply. Thus, microorganisms contained in the (activated) sludge are considered to metabolise amino acids very fast. Based on the available data glycine is considered to be readily biodegradable.

Additional information

Data on biodegradation of zinc 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°C 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.