Engineers at MIT and Imperial College London have developed a new method that can use a mixture of bacteria and yeast similar to the “kombucha mother”
Using this mixture, also known as SCOBY (Symbiotic Culture of Bacteria and Yeast), researchers can produce cellulose with enzymes that can perform multiple functions, such as sensing environmental pollutants. They also showed that they can directly incorporate yeast into materials to form “living materials” that can be used to purify water or make “smart” packaging materials that can detect breakage.
Timothy Lu, associate professor of electrical engineering, computer science, and bioengineering at MIT, said: “We foresee a future that uses biology instead of resource-intensive centralized manufacturing technology that can be used at home or locally. Various materials are grown in production facilities.”
Lu and Tom Ellis, professor of bioengineering at Imperial College London, are the senior authors of the paper, which was published today Natural materials. The main authors of the paper are MIT graduate student Tzu-Chieh Tang and Cambridge University postdoc Charlie Gilbert.
Division of labor
A few years ago, Lu’s laboratory developed a method of using E. coli to produce biofilms embedded with materials such as gold nanowires. However, these films are very small and thin, making them difficult to use in most large-scale applications. In this new study, the researchers set out to find a way to use microorganisms to produce larger amounts of substances.
They thought of creating a microbial population similar to the Kombucha mother, which is a mixture of certain bacteria and yeast. These fermentation plants, which usually contain one type of bacteria and one or more types of yeast, produce ethanol, cellulose and acetic acid, which give kombucha a unique flavor.
Most wild yeast strains used for fermentation are difficult to genetically modify, so the researchers replaced them with laboratory strains of Saccharomyces cerevisiae. They combined yeast with a bacterium called Rhizobium, which their collaborator at Imperial College London had previously isolated from the Kombucha mother. This species can produce a lot of cellulose.
Because researchers use laboratory yeast, they can modify the cells to do anything laboratory yeast can do, such as producing enzymes that glow in the dark or sensing pollutants in the environment. Yeasts can also be programmed so that they can break down contaminants after they are detected.
At the same time, the bacteria in the culture produce a large amount of tough cellulose for use as a scaffold. The researchers designed their system so that they can control whether the yeast itself or only enzymes produced by it are incorporated into the cellulose structure. It only takes a few days to grow the material, and if left long enough, it can thicken to occupy as much space as a bathtub.
Tang said: “We think this is a very good system, very cheap, and easy to mass produce.” “It has at least a thousand times more materials than the E. coli system.”
Just add tea
In order to prove the potential of the microorganisms they called “Syn-SCOBY”, the researchers created a material combined with yeast that senses estradiol, which is sometimes found as an environmental pollutant. In another version, they used a strain of yeast that when exposed to blue light produces a luminescent protein called luciferase. These yeasts can be replaced with other strains that can detect other contaminants, metals or pathogens.
The culture can be grown in normal yeast culture, and the researchers used it in most studies, but they also proved that it can grow in sugary tea. Researchers envision that the culture can be customized to allow people to grow water filters or other useful materials at home.
Tang said: “Almost everyone can do this in their own kitchen or at home.” “You don’t have to be an expert. You only need sugar, you can provide tea to provide nutrition, you also need a Syn-SCOBY mother .”
Researchers report evidence of two main domestication pathways of baker’s yeast
Living materials with programmable functions obtained from co-culture of engineered microorganisms, Natural materials (2021). DOI: 10.1038/s41563-020-00857-5, www.nature.com/articles/s41563-020-00857-5
Courtesy of MIT
Citation: Inspired by kombucha tea, engineers created “Living Materials” (January 11, 2021), which was downloaded from https://phys.org/news/2021-01-kombucha- on January 12, 2021 tea-materials.htmlsearch
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