Slovenia, National Institute of Biology – Marine Biology Station Piran
This bachelor project is a part of GoJelly project, a Horizon 2020 project, that deals with using jellyfish biomass for product development. Jellyfish produce mucus and it has been shown that mucus has the so-called sticky properties that allow micro and nanoplastic particles to be adsorbed. One of GoJelly's main and ideal goals is to produce a biofilter prototype that would enable the collection of microplastics from wastewater treatment plants (“GoJelly”, 2018).
In order to realise this product development with jellyfish mucus, biochemical composition between mucus extracted from different species were examined as well as the physico-chemical stability. Besides that, jellyfish mucus characteristic of capturing microparticles from surrounding seawater was examined. This was important to see if the mucus can be used as a biofilter.
The mucus produced by jellyfish is highly heterogeneous and that makes consistent subsampling difficult. To address this problem, four treatments are applied on the mucus. When analysing the biochemical compounds on the mucus, treated mucus -more specific treatment 4- gives more representative results and has therefore more homogeneous mucus.
Harvesting jellyfish, the laboratory mucus extraction step and the preservation can take a long time. Also, as mucus is rich in proteins, bacteria start to degrade it fast. In order to minimize that, stability experiments were performed. The mucus was stored in the freezer (-20 °C) and replaced after a certain time to -80 °C because bacterial activity is then completely stopped.
This is applied to see if the mucus is still chemically stable after a certain time in the freezer. After the stability experiments, the mucus was analysed for different biochemical compounds. The results show that the chemical composition of the mucus is stable after several days/weeks in the freezer.
The biochemical composition of the mucus from different species shows that in general more proteins are present in the mucus then carbohydrates and the amount of lipids in the mucus is negligible. The amount of carbohydrates, proteins and lipids in the mucus is different between species, but it is shown that the amounts are approximately the same per individual of the same species.
The microparticle analysis shows that not all mucus that is produced by jellyfish is able to capture microparticles (MP) quantitatively because not all mucus has the same physico-chemical properties needed to adsorb MP efficiently. Further analysis need to be performed to see if jellyfish mucus has potential to be used in the product development of the biofilter.
The mucus stability experiments showed that mucus is still chemically stable after storage in the freezer (-20 °C) for several days/weeks, but the microparticle analysis showed that mucus loses the hydrogel structure and adsorptive characteristics when stored in the freezer (-20 °C) for several weeks. The analysis also showed that there is a breaking point of the maximum amount of MP that can be captured by the mucus between the concentration of 8 x 105 MP/L and 1,0 x 106 MP/L, but this needs to be tested further.