MIT engineers have developed a new method to protect microbes from extreme conditions, making it easier to harness their benefits for medicine and agriculture. The approach involves mixing bacteria with food and drug additives classified as “generally regarded as safe” by the FDA. Researchers identified formulations that stabilize various types of microbes, including yeast and bacteria, allowing them to withstand high temperatures, radiation, and industrial processing.
Led by Giovanni Traverso, an associate professor of mechanical engineering at MIT, and Miguel Jimenez, a former MIT research scientist now at Boston University, the team tested their method on four different microbes, including probiotics and microbial therapeutics. The results showed that the formulations could survive harsh conditions, such as temperatures up to 50 degrees Celsius and ionizing radiation, while maintaining their function. This breakthrough has potential applications in space missions, human health, and agricultural uses.
Protecting Microbes from Extreme Conditions: A Breakthrough in Industrial Processing
Microorganisms play a crucial role in various applications, including medicine, agriculture, and space exploration. However, these microbes are often fragile and require protection from extreme conditions to survive industrial processing and storage. Researchers at MIT have developed a novel approach to enhance the stability of probiotics and genetically engineered microbes in harsh environments.
The Challenge of Microbe Stability
When used for medical or agricultural purposes, microbes are typically dried into a powder through lyophilization. However, this process can be toxic to the bacteria, making it challenging to create more useful forms such as tablets or pills. The MIT team aimed to identify additives that could improve the microbes’ ability to survive this kind of processing.
A Workflow for Microbe Stability
The researchers developed a workflow that involves mixing microbes with ingredients from the FDA’s “generally regarded as safe” materials list and then growing them to see which survive best when stored at room temperature for 30 days. This approach revealed different ingredients, mostly sugars and peptides, that worked best for each species of microbe.
Optimizing Microbe Formulations
The team optimized a probiotic called E. coli Nissle 1917, which has been used to treat “traveler’s diarrhea.” They found that combining caffeine or yeast extract with a sugar called melibiose created a very stable formulation of E. coli Nissle 1917. This mixture, dubbed formulation D, allowed survival rates greater than 10 percent after the microbes were stored for six months at 37 degrees Celsius.
Withstanding Harsh Conditions
Formulation D was also able to withstand much higher levels of ionizing radiation, up to 1,000 grays. The researchers hypothesize that the additives may help stabilize the bacterial cell membranes during rehydration.
Maintaining Microbe Functionality
The team demonstrated that these microbes not only survive harsh conditions but also maintain their function after exposure. For example, Ensifer meliloti were still able to form symbiotic nodules on plant roots and convert nitrogen to ammonia after being exposed to temperatures up to 50 degrees Celsius.
The Ultimate Stress Test: Space Travel
Several strains of extremophile microbes were sent to the International Space Station, which is considered the ultimate stress test. The samples recently returned to Earth, and the researchers are now analyzing them to compare their stability in different environments.
Implications for Future Space Missions
This research offers a promising approach to enhance the stability of probiotics and genetically engineered microbes in extreme environments, such as outer space. This could be used in future space missions to help maintain astronaut health or promote sustainability, such as by promoting more robust and resilient plants for food production.
Funding and Collaborations
The research was funded by NASA’s Translational Research Institute for Space Health, Space Center Houston, MIT’s Department of Mechanical Engineering, and the Defense Advanced Research Projects Agency. The study involved collaborations among researchers from various institutions, highlighting the importance of interdisciplinary approaches to addressing complex scientific challenges.
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