Scientists have created new types of ‘living substances’ by tweaking the basics of kombucha – the popular tea drink fermented with a symbolic culture of bacteria and yeast (aka SCOBY).
This type of ‘tea fungus’ – sometimes called ‘mother kombucha’ – can do a lot more than just bitter-tasting drinks, it seems.
By changing the mix of culture, researchers were able to create engineered living materials (ELMs) that could one day have all sorts of practical uses, such as feeling light or looking for contaminated products.
Better yet, the scientists say that these living things can be easily made at home, like watching sourdough starters in your kitchen.
(Imperial College London / MIT)
“While we are still a long way from a future where humans can freely grow their own biological sensors, our new system will move us forward by creating products that are scalable and therefore more likely to be useful in the real world, ”says Imperial College London co – author and author of synthetic biologist Charlie Gilbert.
The roots of routine work go back to 2014, when researchers at MIT engineered Escherichia coli cells to generate biomarkers with non-living structures such as gold nanowires.
Although the invention demonstrated the potential of ELMs, it did so at a microscopic scale, rendering the manufactured products almost useless for practical purposes.
The challenge was to do the same thing on a much larger scale, which eventually led researchers to experiment with kombucha – or, instead, to the mother symbiotic culture.
“We think this is a good system that is very cheap and very easy to make in very large sizes,” says MIT’s first co-author and biological engineer Tzu-Chieh Tang.
“It’s at least a thousand times more stuff than E.coli system. “
(Tzu-Chieh Tang / Christoph Bader / Rachel Smith)
To create their ELMs, the researchers tested a type of laboratory yeast called Saccharomyces cerevisiae, combining it with the bacterium Komagataeibacter rhaeticus.
With a lot of trial and error – including finding the right ratio of yeast to bacteria, and tests to perfect the density of a SCOBY mixture – the researchers eventually succeeded.
Within the engineered culture – known as Syn-SCOBY – the bacteria produce large amounts of cellulose, which is a scaffold structure, in which S. cerevisiae and its enzymes can perform various (programmed) functions, such as sensitizing chemicals in pollutants or pathogens, or producing proteins that glow in the presence of blue light.
These are early days, but this type of system indicates that advanced products, known as ‘smart’, could be made locally in the comfort of people’s homes, rather than being needed. resource intensive manufacturing in a distant factory.
“Almost everyone can do this in their kitchen or at home,” Tang says. “You don’t have to be an expert. You only need sugar, you need tea to provide the nutrients, and you need a piece of Syn-SCOBY mother. “
The results are reported in Natural Materials.