How do students at Caltech celebrate the end of the term? Well, for those of us in Bi/Ge/ESE 178, otherwise known as Microbial Ecology, we concluded a term learning about environmental microbes by indulging in some of their greatest contributions to humanity – fermented foods! 

Microbial Ecology is one of the many microbiology classes offered at Caltech, taught by the incredible Professor Victoria Orphan (if you want to learn about another wonderful class by Dr. Orphan, check out our other blog 🙂 – where we went on a life-changing trip with Prof. Orphan and taught her how to 0.5 🙂 ). Microbial ecology describes the way that microbial life (bacteria, archaea… basically any microscopic form of life!) exists and interacts with the environment. We learned about how microbes organize themselves into communities, the different ways in which they interact with each other, how communities are influenced by environmental limitations or predation, and how microbial metabolism influences the cycling of nutrients around the world. Microbes may be tiny, but they exist on almost any part of the Earth you can imagine – inside of animals (including you!), in the atmosphere, the bottom of the ocean, and even deep in the Earth’s crust! This makes them extremely important in regulating the way that carbon and nitrogen move between the biosphere, geosphere, and atmosphere, which is part of why I (Emma) think they’re so interesting to study! Before I end up spending this entire blog talking about how cool microbes are, I’ll stop myself and say that this is just a small taste of the super fun topics we went through in the class (you’ll have to come to Caltech and take the class to hear the rest 😉) . 

Thus, to conclude this fascinating class, we had no choice but to celebrate the incredible roles that microbes play in our lives by trying a selection of fermented foods, one of the most direct ways many of us interact with microbial life on a daily basis. 

The week before the Fermentation Fest, Dr. Orphan invited us to her house to prepare the food that the microbes would ferment in time for our end-of-term celebration. A few students from the class, including myself (Emma), chopped and pressed a variety of vegetables to prepare kimchi, sauerkraut, and fermented radishes and leeks. We added the spices, salt, and distilled water until the vegetables were completely submerged, trying to minimize the oxygen left in each jar to select for the halophilic (salt-loving) microorganisms that would ferment our food! 

About a week later, after pH testing our fermented goodies to make sure they were consumption-safe, they were brought to class to celebrate the end of a great term. The fermented foods we made were supplemented by others that Dr. Orphan brought: kombucha, cheese, sourdough bread, pickles, fermented coffee, chocolate, miso soup… honestly, I had no idea that so many things were fermented! 

In addition to eating tons of great food, we listened to podcasts that we’d made in pairs as our final project for the class. Each group was tasked with interviewing a microbe that was globally important for one of the UN Sustainability goals, allowing us to not only learn about how cool microbes are intrinsically, but also about how much good they can do for the world! Juni wasn’t in the class, but she came along to join in the fermentation fest, enjoying all of the fun fermented foods and creative podcasts without having to do any of the coursework.

Enjoy some photos of the food from the event, and remember that the next time you enjoy any of these foods, you have microbes to thank! 

OUR SAMPLED FOODS:

Some of the podcasts:

This was Emma’s podcast, which was an interview with Thermus aquaticus, the microbe most commonly known for its role in PCR (TAQ!). In addition to lots of scientific facts and course-relevant information, the podcast was also extremely funny, and Emma did a great job impersonating the microbe 🙂

Some fun facts I (Juni) learned about Thermus aquaticus…

• Prefers super hot environments (> 75°C) and can survive in conditions up to 90°C
• Can have flagella or can just float
• Heat and radiation-resistant bacteria
• Here since the start of life (billions of years ago!)
• Horizontal gene transfer allows for genome-diversity

This was another podcast by two of our classmates. Instead of hosting an interview between a human and a microbe, this podcast conversation was between two symbiotic organisms: the bobtail squid and the microbe, Vibrio fischeri. Like Emma’s podcast, this one was really funny, and the well-researched presentation did a great job explaining the nuances of the symbiotic relationship between the squid and V. fischeri.

Some fun facts I (Juni) learned about Vibrio fischeri…

• Colonizes many fish and squid
• Microbes are drawn in during the morning via cilia and expelled the next morning
• Aerobic and anaerobic metabolism
• Microbes in the crypt lose motility, but the crypt is a protective environment (preferable to free living)
• Some strains are bioluminescent!

Anyway, we hope you enjoyed our recounting of fermentation fest! And, if you have a free spot in your schedule, Bi/Ge/ESE 178 is a fantastic class to add!