An unpublished study that emerged from a challenge launch to a third-year biotech class by Teresa Rocha Santos, lead researcher at the Center for Environmental and Air Studies at the University of Aveiro (UA) end up producing a discovery thanks to the tenacity of a young student, Ana Paços, that Zalerion maritimus, a very common fungus on the Portuguese coast, in an environment similar to that of the sea polluted with microplastics achieves, in only seven days, the reduction of 77% of that toxic material. For the three researchers involved in this research "this is undoubtedly the first study to present bioremediation strategies, a process that uses living organisms to reduce or remove contaminations in the environment, in this specific case of microplastics. Therefore, this work can be considered a first step and a contribution to the solution of this problem ". This is also the first ecological solution ever discovered to combat plastics in the oceans, since optimizing the rare appetite of the fungus resorted to a solution offered by the sea itself. A scientific finding, according to the editor of "Sciene of The Total Environment", where the study was published, opened the door to "a truly new field of investigation."
How did you discover the qualities of this fungus that absorbs microplastics in the ocean?
Teresa Rocha Santos: It is a fungus that is called Zalerion maritime and has the ability to degrade cellulose. So, it is found in the wood in the ocean. Given that cellulose is a rather complicated polymer, we felt we would be able to degrade plastic that is made of polyethylene and this was the case we tested. Another aspect that led us to choose this fungus is that it exists on the Portuguese coast. It was an interesting proposal if we wanted to move forward with the plastic treatment system on our coast. It is a species that already existed and there would be no problem introducing something new.
If it exists on the Portuguese coast, the fungus must be used in controlled areas, why? If we let this fungus act openly does it spread uncontrollably, as algae blooms appear in rivers and reservoirs?
TRS: Exactly, the whole body has a tendency to do that. We cannot introduce it in large quantities, because otherwise it can induce an imbalance in the ecosystem. So, what we must do is create controlled locations to introduce more or less amount of fungus and not leave it to the rest of the ocean.
How can you control this with nets?
TRS: In the same way that algae and fish are produced in aquaculture, a fungus can also be produced under the same conditions. We are still thinking about what we are going to do in the next phase, before we were doing a study with aluminals, then we went to the aquariums where we are now. Since we are in the zone of Aveiro and we have abandoned salinas we will create the necessary conditions to make there a kind of treatment station. This will always be a test, it must be away from aquacultures and other activities of this kind, because we have to be sure that we will not produce any damages, we must properly study the fungus to degrade the microplastics and must to be sure that water contains no toxic components.
Another question I have is if this fungus has any natural predator? That is, there are always living organisms that eat others, this question can be put in the future when you place the Zmaritimum in nets in the ocean?
TRS: We do not know, because this fungus is very little studied, was also one of the reasons why we thought it was also interesting to study it at the time. There are indeed predators, but if we have a closed station this question does not arise, we do not have that problem at the outset. We have collections of this and other organisms that can be purchased to be reproduced in laboratories, so there is no problem of being exhausted in the ocean.
This is a pioneering study, it was published in a scientific journal, but how many years have you been focusing on this study?
TRS: This study started a year ago following an invitation I received to write a book with other authors on microplastics. At the time we found it interesting to try to find, everyone is trying, a solution for their monitoring in the ocean, because it is very important and we have no idea where they exist and in what quantity. Therefore, it is necessary to carry out an exhaustive monitoring, on the other hand, we also felt that a solution was necessary and I decided to launch the topic in the third year of the biotechnology and chemistry department of the AU. A student, Ana Paços, chose this theme because she found it interesting and came to work with us. She was very interested and an excellent student and with the partnerships that we obtained in the laboratory to execute these works we ended up obtaining these results. The work there has already evolved in another way and as she was so interested, this year she wanted to continue working with us on a volunteer basis, although we have other people involved in this subject, she decided to do the master's thesis with us on this same theme. We currently have a team of three people to get the results faster.
This second phase, of testing this fungus in a controlled environment will be how long?
TRS: We do not know yet, because we are doing the study with aquariums, we have been in this aquatic phase since February. From the results we get, which will be between September or October, we have published these results again and made a decision about what we are going to do next. At this point, we decide whether we have advanced more or only in a while and how we are going to move forward, because we have not yet got that notion.