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 (IC50 = 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.