Depcb

Tilia Selldén and Tim Eckerström, are members of DePCB which is a group of eight students from Chalmers University of Technology and University of Gothenburg who are conducting a research project in the field of synthetic biology which involves the use of baker’s yeast and enzymes to break down the environmentally toxic substance PCB. If you followed all of that, you might want to check out DePCB as they compete at the upcoming International Genetically Engineered Machine competition in Boston. And even if you didn’t follow all of that, you may still want to check out this interview we did with Tilia and Tim:

Tilia: So, synthetic biology is about taking a microorganism and improving one of its functions. The microorganism could be our own cells or bacteria, for example, or it could be yeast or algae or some other thing that most of us are unfamiliar with.

Tim: Let's say that an organism proves to be good at digesting plastic, or in other words, part of its energy supply comes from plastic. In that case, we would begin to cultivate the organism in such a way that it would eventually thrive all the more on plastic. In this way, we would produce a new bacterium that’s a little bit better than the previous one at digesting plastic — a kind of super bacterium with cultivated characteristics. Last year's Nobel prize for chemistry went to research with a similar approach. For us, we aim to combat the environmental toxin PCB (polychlorinated biphenyl) by modifying yeast with this type of new, PCB-digesting characteristic.

PCB consists of a carbon + hydrogen molecule with a lot of chlorine attached. It isn't really easy to understand why this particular compound should be more dangerous than any other compound, but the dangerous part has a great deal to do with the attached chlorine — it is what makes PCB very stable and tough to get rid of in the environment. 

Tim: What I find really cool about our project is how we’ve combined multiple enzymes to try to combat PCB. Enzymes are proteins that can catalyze reactions, including the break-down of other substances. Our research led us to two useful enzymes, one of which is extremely good at removing chlorine from molecules like PCB that have a great deal of chlorine attached. The other enzyme is able to remove a little less chlorine, but the important thing about our project is how we combined these two enzymes so that together they're able to take care of the majority of the PCB breakdown process. There’s a total of 209 different varieties of PCB molecules, and the amazing thing about our enzymes is that it's theoretically able to break down a great number of them. This is the general idea of our project, and it's what we're busy developing.  

Tilia: When we started the project, we quickly discovered that pre-existing research was pretty scant and poor quality. At first we thought “Okay, we have practically nothing to go on,” but really, that just makes it all the more exciting.

Tim: Exactly. We're fumbling around in the dark, but we're having fun!

- Tilia Selldén

Tim: This is a student-driven project with a duration of only six months, and we realized pretty quickly that the project was too big for so brief a period. We need more time, but we've succeeded in doing the most important thing — integrating one of our proteins in a yeast. This has provided proof of concept and gives us great hope in being able to integrate more proteins in yeast in the same way.

Tilia: Speaking of yeast, we use perfectly ordinary baker's yeast, just like we use to bake buns. We do so because it's not dangerous in any way. It also seems that baker's yeast can cope with the levels of PCB that exist in the environment. 

Even if we don't have time to finish everything within the project’s six month timeframe, everything we learn will be added to a shared knowledge bank. Our work is based on a project that was carried out by a prior group in Paris in 2013, and after us, hopefully another group will take over and continue building on the research. This is the way student projects make progress. It won't be just eight people who save the oceans, but team after team after team who collaborate and share one other's knowledge.

Tim: So far, the biggest pitfall to our project is known as August, and it's mighty deep. Absolutely nothing happened in August. We tried and tried but got no results. In biology, it's not the case that A always leads to B; sometimes it leads nowhere and other times it might lead to C.

Tilia: Indeed, we're working with living organisms and they don't always behave the way we'd like them to. Sometimes they grow and thrive, other times they don't grow at all. Sometimes we have an explanation, other times we don't. This unpredictability is probably the biggest obstacle, but it’s instructive all the same. 

How do we relax? We relax by playing ping-pong! I also do a lot of martial arts training—Taekwondo, specifically. The way I see it, I work with my head at the university and with my body in my spare time, and I think that's a great combination. 

Tim: I stick strictly to working out in my head! During the days I work logically, and in the evening I work creatively. Right now, I'm taking a course in improv theater and I'm really into role-play. Trying out how it feels to be someone else really helps me relax. And the people in that world are also entirely different from the people here at university, where everyone likes to be buried in their projects 50 hours a week. It's great to get out of that bubble every now and then. 

Tilia: We also relax by thinking about our upcoming trip to the USA, where we’re scheduled to present our project at one of the biggest annual biotech conferences, iGEM in Boston. In other words, we're about to be judged — but it feels more like a reward for all of our hard work. There will be more than 350 teams competing from all over the world, and we’ll be presenting what we’ve done over the past year, how we’ve done it and everything else in front of the judges.

Ultimately though, it would be a dream come true for me if researchers are able to use our project’s principles to break down all kinds of environmental toxins, not just PCB. In other words, I hope this research helps us exploit the power of yeast and microorganisms to the fullest extent. It could one day be used in treatment plants where different types of yeast remove different toxins, for example. This method isn't too hard on the environment and it’s nowhere near as expensive as chemical treatment. Plus, while it’s prohibited to build on construction sites where there’s a lot of persistent PCB present, there are many companies that frankly just don't give a damn and build anyway. So if our project can help find a good, cheap solution to removing PCB, we'll be helping to solve a major challenge.