Cancer researchers to market crayfish
By studying marbled crayfish, Sina Tönges and Frank Lyko, from the German Cancer Research Center (DKFZ), were able to gain new insights into the development of cancer. Now the researchers want to market the animal: As a source of nutrition and a bioresource.
Mr. Lyko, Ms. Tönges, how does a scientist at an institution dedicated to researching cancer, of all things, come up with the idea of breeding crayfish?
Frank Lyko: In epigenetics we investigate how cells acquire their specific functions, and we are concerned with the question of what influence the environment has on the genes. In so-called epigenetic mechanisms, the genetic code remains intact, but external areas of the genetic material are altered, which can influence gene activity under certain circumstances. In the development of tumors, we know that epigenetic processes are disrupted. This offers new approaches to understanding disease processes, as well as new diagnoses and therapeutic options. In my search for new model systems, an acquaintance drew my attention to marbled crayfish. They are relevant because they reproduce by cloning. This means that each animal is descended from a mother animal. What is surprising is that the animals adapt to all kinds of environmental conditions, and do so within a few months. This is the parallel between crayfish and cancer. Tumors also develop as clones, a single cell is the origin of the tumor. It keeps multiplying clonally and adapting epigenetically. To study these mechanisms, we have established a marble crayfish colony here in the lab.
Sina Tönges: As part of my doctorate I went to many lakes in Germany for this, spending night after night in search of the crayfish together with a Madagascan colleague. Interestingly, the animals are also very widespread in Madagascar, where they are eaten. After initial hesitation, they are now a hugely popular food there. When I first introduce the animals somewhere, the most common question is: Can you eat them and do they taste good? At some point we thought, we have to try this. My brother is a chef. I asked him if he could prepare a few, which he did, and it worked out wonderfully. They were very tasty. That's how the idea came about that we could also use the animals outside of epigenetic research.
What makes the marbled crayfish so special that you are venturing down the spin-off path with it?
Frank Lyko: The marbled crayfish is extremely undemanding, and it is a good food converter. For one kilogram of marbled crayfish, it only needs 1.4 kilograms of feed. That's an extremely efficient way to convert food. And the parthenogenetic, or unisexual, mode of reproduction is also a plus. There are only females. That means little aggression and therefore little stress.
Sina Tönges: Exactly. Purely female populations are often less aggressive than mixed ones. That's why, for example, people are also trying to genetically modify salmon or shrimp so that they are purely female. But parthenogenesis in the marbled crayfish has other advantages. The fact that the animals are genetically identical is also reflected in their growth, resulting in very homogeneous products in the long run.
What kind of products do you have in mind?
Sina Tönges: Our concept is to utilize the whole animal. There's the meat, of course. We have already cooked up three different variants of pasta sauce on a test basis. Then comes the chitin. This is probably the most sought-after raw material for bioplastics. It is found in the shells of crustaceans and has so far been obtained mainly from the shells left over from shrimp processing. We examined the marbled crayfish for this and found that it contains three times more chitin than a shrimp. In an initial product showcase, we worked with a company in Brazil to develop biodegradable straws from it.
Frank Lyko: Another raw material is astaxanthin. When you throw a lobster into the cooking pot, it turns red. The reason for this is precisely this pigment, which is contained in the shells of all crustaceans but is covered by proteins. When heated, the structure of the proteins is destroyed, and the color appears. Marbled crayfish shells contain incredible amounts of astaxanthin. This is a powerful antioxidant that is sought after not only as a food supplement, but also as a food coloring agent. We want to utilize that as well. We’re building on two core technological components: One is aquaculture production, and the second is the biorefinery. With aquaculture production we produce the animals in a closed system, whereas the biorefinery breaks down the marbled crayfish into its components of meat, chitin, astaxanthin, protein residues and minerals.
Let's stay with aquaculture production for a moment. How did you think of it?
Frank Lyko: The first advice we heard from the experts two years ago was: Just send the animals to Southeast Asia. There are people there who know how to do that. They'll put them out in some field and then it will work. But we didn't want to do that because of the ecological concerns about this form of aquaculture. In addition, the marbled crayfish is an invasive species, so we don't want to release the animals into the wild. Our focus from the beginning was on closed aquaculture systems. To do this, we traveled to Southeast Asia and looked at shrimp farms there. But shrimp need a very high water column. These are usually tanks several meters high. Crayfish, on the other hand, are bottom dwellers. They don't swim. So why should we circulate and clean so much water when we can do it with much less. We wanted to do everything radically differently right from the start. We found the technical solution for this not in Southeast Asia, but with a company in Vienna. We are now working with them on a customized system for our crayfish. It is a vertical system in which we keep the animals in a kind of drawer and stack them on top of each other. It all fits into a standard freight container. You fill it with water once, add the crayfish, connect the electricity and feed regularly. Then the unit produces self-sufficiently and it can be stacked and combined as required because the containers for freight transport are internationally standardized.
Sina Tönges: The closed system gives us many advantages. Apart from minimal evaporation, there is no water loss. Of course, this also makes it attractive for areas where there is little water available. In the desert, for example. By controlling the water, we also don't have to add antibiotics. We have much better control over the feed. Put it all together and you have a very different product. A much more assured product. That's our goal.
And the biorefinery?
Frank Lyko: We have already done a lot of preliminary work there, too. Take chitin, for example. There is already a large industry in Southeast Asia that extracts it from shrimp shells, but with a lot of caustic soda and hydrochloric acid. That is not very environmentally friendly. We didn't want that, so we developed an alternative protocol that is much more environmentally friendly. We are currently applying for a patent and we have now established the biorefinery in our laboratory.
You have already put a lot of research and development into your project, but what about the business aspect?
Frank Lyko: We are now part of the Helmholtz spin-off program and were able to recruit a great coach, Lukas Bosch, for our team. He supports a lot of companies that really want to work sustainably. He coaches our team regularly on business readiness and opens up a network for us.
Sina Tönges: And we have now applied for an accelerator. It's called Seedhouse and it's in Osnabrück. It's THE German accelerator for food and agritech and extremely competitive. Only 10 percent of the applications are accepted. In December, we received the confirmation that we had been accepted. I think that speaks for our innovative strength.