A new material inspired by the mother of kombucha

Engineers at MIT and Imperial College London have developed a new way to produce strong, functional ingredients using bacteria and yeast similar to the “Kombu Tea Mother” used to ferment tea.

Also known as SCOBY (a symbiotic culture of bacteria and yeast), this mixture was used by researchers to produce cellulose embedded with enzymes that can perform functions such as sensing environmental pollutants. He also showed that yeast can be incorporated directly into materials to create “living materials” that can purify water and create “smart” packaging materials that can detect damage using fluorescence.

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Timothy Lou, an associate professor of electrical engineering and computer science and biotechnology at the Massachusetts Institute of Technology, said:

Professors of bioengineering at Imperial College London, Lu and Tom Ellis, are senior authors of a treatise detailing their work. Nature Materials.. The lead authors of this treatise are Tzu-Chieh Tang, a graduate student at MIT, and Charlie Gilbert, a postdoc at the University of Cambridge.

Lu’s lab was formerly E. We were developing a method using coli to produce biofilms with embedded materials such as gold nanowires. These films are so small and thin that they are difficult to use in most large applications. In a new study, researchers set out to find ways to improve scalability.

They considered creating a microbial population that resembled the mother of kombucha, a mixture of certain types of bacteria and yeast that gives kombucha a unique flavor.

Most of the wild yeast strains used for fermentation are difficult to genetically modify, so researchers replaced them with the yeast strain Saccharomyces cerevisiae.

They can produce large amounts of cellulose by combining the yeast Komagataeibacter rhaeticus, which was previously isolated from the mother of kelp tea by a collaborator at Imperial College London.

According to MIT, cells in yeast laboratory strains can be designed to produce enzymes that glow in the dark and to sense pollutants in the environment. Yeast can also be programmed to break down after detecting contaminants.

Bacteria in culture produce large amounts of cellulose that act as scaffolds. Researchers have designed the system to control whether the yeast itself, or only the enzymes it produces, are incorporated into the cellulosic structure. The material can grow in a few days and can eventually be thick enough to occupy a space as large as a bathtub.

“I think this is a great system that is very cheap and very easy to manufacture in very large quantities,” Tang said in a statement. “This is at least 1000 times more material than the E. coli system.”

To demonstrate the potential of their microbial culture, called Syn-SCOBY, researchers have created a material that incorporates yeast that senses estradiol, which is sometimes seen as an environmental pollutant. In another version, they used a strain of yeast that produces a protein (luciferase) that glows when exposed to blue light. These yeasts can be exchanged for other strains that detect other contaminants, metals, or pathogens.

The culture can be grown on the normal yeast medium that researchers used for most studies, but it has also been shown that it can be grown on sugar-containing teas. Researchers predict that the culture can be customized for home use to grow water purifiers and other useful materials.

“Most people can do this in the kitchen or at home,” says Tang. “You don’t have to be an expert. You just need sugar, you need tea to provide nutrients, you need a Syn-SCOBY mother.”