Intestinal bacterium repairs marl walls

Intestinal bacterium repairs marl walls

Another prize for Maastricht students

26-03-2024 · Interview

Maastricht students were able to take a bacterium that is normally found in the intestines and use it to repair cracks in marl. They were recently awarded for this (again). “The first time that the bacterium created limestone, we held a party.”

Maastricht and marl are intimately connected: the light-coloured limestone adorns many facades in the Limburg capital. Beautiful, but it also requires a lot of maintenance: marl is soft, not resistant to acid rain, discolours easily, and cracks develop quickly. Methods do exist to counteract this, but they are not ideal, say Floor Vervuren and Fien Eickmans. Some actually lead to unwanted discolouration; others are “very labour-intensive, because they involve replacing a whole block of stone”.

DNA origami

There should be an easier way for that, thought Vervuren, Eickmans, and nine other students from the Faculty of Science and Engineering, who were supervised by associate professor of synthetic biology Erik Steen Redeker. As ‘Team SublimeStone’ (a play on the word ‘limestone’), the eleven participated in iGEM last year, an international competition for research projects at the interface of biology and technology. Their solution for the marl problem? A genetically modified bacterium.

Or actually two, Vervuren and Eickmans explain: the one is adapted in such a way that it creates “DNA origami”: a strand of DNA that spontaneously forms a kind of spider web in the crack. The second one had an enzyme added to it that uses CO2 from the ambient air to form bicarbonate. “Combine this with calcium, and it creates calcium bicarbonate, or limestone,” says Vervuren. “We did that by adding both bacteria to a gel that also contained calcium ions.” The calcium then attaches to the ‘spider web’ and fills in the crack.

Team SublimeStone, with, standing third from the left, Fien Eickmans,
and sitting, second from the right, Floor Vervuren. | Foto: Chris Damour

There is a photograph on Team SublimeStone’s website of a bottle containing small white lumps: the first bacterial limestone created by the team. “It was really cool to see that it actually worked,” says Vervuren. More so, Eickmans adds: “There was a party.”

Apart from the party, their work was worth a golden medal and a top-10 classification in the iGEM competition. On top of all that, they received the public award last week at the award ceremony for the annual Prins Friso Engineering Prize. “So cool, we did not expect that,” they say, even though compared to last year, celebrations were more modest. “Princess Beatrix and princess Mabel were sitting in the first row,” Eickmans clarifies. “So you don’t scream when you win.”

More research needed

And now? Will the gel soon find its way onto the shelves of your local DIY shop? The two laugh: we are not there yet, for sure. Team SublimeStone is proud that in such a short time – “we had four months’ time for the lab work” – it was proven that the idea works. “But for practical applications, there is still a lot of research to do,” says Vervuren. For that, more equipment than is currently available at FSE is needed, says Eickmans, in order to test how strong the newly created marl actually is. More research, and also more time, which is very scarce now that many team members are in the final stages of their bachelor’s programmes and have to write their theses.

The work hasn’t come to a complete standstill though. Until now, the team used E. coli, a bacterium found in the large intestine in humans. However, it is not very resistant to heat, which prompted them to check if a different bacterium, Bacillus Subtilis, could be used. This also forms spores, small ‘dormant’ particles that can survive in a stone, Eickmans explains: “If a crack occurs and water seeps in, the spore ‘wakes up’. The idea is that it then repairs the crack by itself.”

Photo: Team SublimeStone

Categories: news_top, Science
Tags: Students, Research, Marl, Limestone, Faculty of Science and Engineering,instagram

Add Response

Click here for our privacy statement.

Since January 2022, Observant only publishes comments of people whose name is known to the editors.