Diverse Functional Materials Inspired by Yeast and Bacteria

Innovation: Academia

MIT

2021

Image: Sam Moqadam / Unsplash / CC BY SA - Creative Commons Attribution + ShareAlike

Sense Chemicals (Odor, Taste, etc.) From the Environment

Chemicals are important for signaling and communication among living systems, either intentionally (such as when two living systems try to find one another) or unintentionally (such as when a plant emits a chemical signal that an herbivore can use to find a tasty bite). They are also important for other uses, such as navigating or finding sources for minerals. But chemical signals are often relatively weak and disperse when moving through water or gases. Therefore, detecting them requires specialized abilities, including a way to determine where they are coming from. A well known example of sensing chemicals can be seen in ants following a pheromone trail laid down by others in their colony to locate a quality and abundant food source.

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Sense Temperature Cues From the Environment

Some living systems use their ability to perceive temperature to find prey or avoid predators, or as a way to gain information about their environment, such as whether they are near a warm or cold place. Temperature gradients can be subtle and modulate as they travel through water, air, or solids. Living organisms must therefore have a variety of thermal sensors appropriate to a given medium (liquid, gas, solid). Some even have a way to “visualize” a signal’s source. For example, the rattlesnake has heat sensors with thousands of nerve endings located in pit-shaped holes on each side of its face. The sensitivity of the pits overlaps, giving the snake a bifocal image of the heat’s source.

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Sense Disease in a Living System

Living systems that can detect diseases within themselves, or within other living systems, can direct resources toward curing those diseases or preventing their spread. This type of sensing environmental cues is not well known, probably because of the difficulty studying disease detection, including the difficulty in providing scientific proof. However, there are a few known examples, such aschimpanzees that detect illness in themselves and self-medicate through eating plants with medicinal benefits.

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Living materials from MIT can be programmed to sense environmental pollutants or glow in the dark.

Benefits

Scalable
Resilient
Reduced costs

Applications

Medical diagnosis
Sensors
Water filtration

UN Sustainable Development Goals Addressed

Goal 9: Industry Innovation & Infrastructure
Goal 12: Responsible Production & Consumption

The Challenge

Engineered living materials have the potential to replace common ‘non-living’ materials used in many applications today. Although the living materials are capable of achieving a variety of functions, they have been found to be too sensitive and weak for large-scale applications.

Innovation Details

The living material called Syn-SCOBY is made from a mixture of bacteria and yeast. The yeast strain is Saccharomyces cerevisiae, a common laboratory strain. The bacteria is Komagataeibacter rhaeticus, which was isolated from a kombucha mother. It is known to produce large quantities of , which serves as a tough and resilient scaffold for the living material. The material is designed so that either the yeast or just the enzymes they produce are incorporated into the structure. The engineered yeast can serve a variety of functions, such as producing enzymes that glow in the dark, or sensing pollutants in the environment. The yeast can also be programmed so that they can break down pollutants after detecting them. The material can be grown in just a few days, and can grow to the size of a bathtub if left long enough.

Biological Model

Symbiotic cultures of bacteria and yeast (commonly known as SCOBYs) are cultivated in many kitchens or factories as part of the process of producing fermented foods such as kombucha or kimchi. The yeast naturally ferment the available sugars while the bacteria convert ethanol (a byproduct of the fermentation) into lactic or acetic acid, giving the foods their characteristic sourness.

References

Journal article

Living materials with programmable functionalities grown from engineered microbial co-cultures

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Diverse Functional Materials Inspired by Yeast and Bacteria

MIT

Sense Chemicals (Odor, Taste, etc.) From the Environment