Heterotrophic Microalgae Cultivation Using Jellyfish Protein Extract to Produce Bioactive Peptides

Jellyfish are often seen as a nuisance, and while attempts have been made to use jellyfish waste as fertilizer and food, they have not proved fruitful. In this study, proteins extracted from jellyfish ( Aurelia aurita ) are investigated as a novel nutrient source in culture medium and tested on aerial microalgae under heterotrophic condition. Results demonstrated that Vischeria helvetica KGU-Y001 heterotrophically grew in the extract-containing culture medium in the presence of light. Decomposition of the extracted protein in the culture medium containing V . helvetica cells was verified both in the presence and absence of light. The inhibitory activity of angiotensin I-converting enzyme (ACE) was measured in the culture medium when in the presence of light. The hydrolysates in the medium were separated using a gel filtration column and a peptide fraction with approximately 400 Da, and high ACE inhibitory activity (IC 50 = 72 µg mL −1 ) was obtained. The results presented here will help to facilitate the development of culture systems with jellyfish waste as a resource for culture medium. Graphic Abstract