[No public or meaningful name is available]

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

The provided key study was performed on the protein hydrolysate derived from vegetables and considered a relevant source for the read-across assessment of the properties of corn gluten hydrolysate (analogue approach).
All protein hydrolysates can be regarded as analogues with similar properties on basis of having common precursors (proteins) and common breakdown products (amino acids, peptides) through physical and/or biological processes which result in structurally similar degradation products (similarity through biotransformation).

The animal and vegetable cells are formed mainly by proteins, which constitute more than the half of the dry weight of the cell. These components and their degradation products are constantly present in the animal and human diet and in the environment.

After ingestion, proteins are hydrolyzed in the gastrointestinal tract by proteolytic enzymes derived from the pancreas resulting in the release of dipeptides, tripeptides and free amino acids. Digestion is further enhanced by proteases, such as aminopeptidase N, that are located in the plasma membrane of the intestinal cells. Single amino acids, as well as di- and tripeptides, are transported into the intestinal cells from the lumen and subsequently released into the blood for absorption by other tissues. The final digestion products are then used by the cells for the biosynthesis of new specific proteins, or they can then undergo further amino acid catabolism, where they are utilized as an energy source.

The proteins present in the environment as a part of dead animal and vegetable tissues are subject to biodegradation by microorganisms. The products of the degradation could be peptides, free amino acids for new protein synthesis or inorganic compounds in case amino acids are further catabolized for energy production. These degradation products are common for all the proteins and naturally present in the environment.

Proteins derived from different sources has different amino acid profiles. The hydrolysates also have different compositions depending on the manufacturing process and hydrolysing agents used. Differences also include oligopeptides and peptides chains length and structure. While these differences might be meaningful when considering the use of protein hydrolysates as food supplements and their beneficial impact on health condition, they do not make significant difference for the toxicological or ecotoxicological profiles of particular hydrolysates. All proteins, regardless their source and structure, are in the end subject to the same degradation processes and metabolic pathways.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

24 d

Dose descriptor:

other: the study focused on growth enchancement by the test substance, no toxic effects were observed

Effect conc.:

> 400 mg/L

Remarks on result:

other: highest concentration tested

Conclusions:

The addition of protein hydrolysate to the cyanobacteria culture didn't reduce the growth of the organisms at the tested concentrations.
The addition of the tested substance in fact enchanced the growth of Spirulina. It can be concluded that the substance is not toxic to cyanobacteria.

Description of key information

Not toxic to cyanobacteria.