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Could a tiny organism help address the climate crisis? Introducing UTEX-3222, affectionately known as ‘Chonkus,’ a type of cyanobacterium found in the volcanic CO2 seepage near Vulcano, Sicily. Similar to other photosynthetic cyanobacteria, Chonkus absorbs CO2 and integrates it into its structure. What makes UTEX-3222 unique is its ability to grow rapidly and in high densities, enabling it to consume CO2 more efficiently than many of its counterparts. Additionally, Chonkus is 5 to 10 times larger than the average microbial cell, which allows it to sink quickly after CO2 absorption, facilitating carbon sequestration or repurposing for biomanufacturing.
A global team of researchers from the United States and Italy has identified a new strain of cyanobacteria, or algae, sourced from volcanic ocean vents, notable for its rapid growth in CO2-rich environments and its propensity to sink in water. This strain, dubbed “Chonkus,” was discovered off the coast of Sicily’s Vulcano Island, where shallow volcanic vents disperse marine CO2. The findings are detailed in a study released today in Applied Environmental Microbiology.
“Carbon dioxide in the ocean is quite dilute among other molecules, which affects the growth of photosynthetic organisms there. We wanted to see what would happen if we explored areas with abundant carbon, where some organisms might have adapted to thrive,” explained Max Schubert, Ph.D., a co-author and former staff scientist at Harvard’s Wyss Institute, now serving as Lead Project Scientist at Align to Innovate. “This naturally occurring strain of cyanobacteria presents multiple beneficial traits for humans, such as dense growth and a natural tendency to sink, making Chonkus a compelling organism for future carbon reduction and biomanufacturing efforts.”
From the ocean depths to research labs
Schubert collaborated with Braden Tierney, Ph.D., after they met as lab colleagues nine years ago but only began working together in 2016 at Harvard Medical School (HMS). Schubert, who focused on developing tools for bacterial genome evolution, proposed a project to harness the capabilities of cyanobacteria in combating climate change at the HMS Consortium for Space Genetics’ 2019 Symposium, winning a grant that launched his research in this area.
Meanwhile, Tierney, who was a postdoc with Schubert’s advisor, came across a study on shallow seeps where gases seep into sunlit waters, leading him to realize that there might be photosynthetic microbes capable of efficiently absorbing dissolved CO2. Teaming up with Sicilian researchers Marco Milazzo, Ph.D., and Paola Quatrini, Ph.D., who were studying nearby seeps, Tierney secured funding for an expedition aiming to collect samples from these CO2-rich environments and enlisted Schubert’s support for studying the resultant cyanobacteria.
They assembled a diverse team from various institutions, including the Wyss Institute, HMS, Weill Cornell Medical College, Colorado State University, the University of Wisconsin-Madison, MIT, the National Renewable Energy Laboratory, and several Sicilian universities. The team ventured into the waters off Vulcano, equipped with SCUBA gear, to gather samples from the CO2-enriched shallow seeps and shipped these samples across the Atlantic for further study in Boston.
A microbe’s quirk becomes a boon for humanity
To encourage growth of the target cyanobacteria, researchers replicated optimal conditions: warm temperatures, abundant light, and ample CO2. This led to the discovery of two fast-growing cyanobacterial strains: UTEX 3221 and UTEX 3222, with the team deciding to focus on UTEX 3222, noted for its single-celled structure that made it easier to compare with other strains.
UTEX 3222 developed larger colonies and individual cells than previously known fast-growing strains, hence the nickname Chonkus. It exhibited higher density growth, contained carbon-rich storage granules, and had increased overall carbon content, making it potentially valuable for carbon sequestration and production purposes. Remarkably, Chonkus formed dense pellets, likened to “green peanut butter,” that quickly settled at the bottom of sample tubes, while other strains stayed suspended. This sinking behavior is advantageous for industrial applications, as concentration and drying of biomass can account for up to 30% of production costs.
“Many traits seen in Chonkus may not be beneficial in its natural habitat but could be advantageous for human use. Normally, aquatic organisms grow at low density, yet achieving high density at elevated temperatures is crucial for many industrial manufacturing processes and enhances carbon sequestration,” Tierney commented. “The vast microbial diversity we can access could provide better solutions than solely engineering traits into lab-grown E. coli.”
The team is enthusiastic about various potential applications for Chonkus or its modified forms. Many organizations are exploring using fast-growing organisms for carbon capture, and Chonkus could fit well into these initiatives. Several valuable products such as omega-3 fatty acids, astaxanthin, and spirulina are typically produced using algae and may be produced more efficiently with a quick-growing and dense strain. Additionally, since cyanobacteria absorb carbon from their environment for growth, they can simultaneously accomplish carbon sequestration and biomanufacturing.
Samples of UTEX 3222 and UTEX 3221 are preserved and available for research use from the Culture Collection of Algae at the University of Texas, Austin.
Encouraged by their first expedition’s success, Tierney co-founded with co-authors Krista Ryon and James Henriksen a non-profit called The Two Frontiers Project to investigate how life thrives in extreme habitats through innovative scientific expeditions. The group has since completed further explorations in Colorado’s hot springs, the Tyrrhenian Sea, and the Red Sea coral reefs, focusing on microbes for three primary purposes: carbon capture, sustainable CO2 upcycling, and coral ecosystem restoration.
“The traits found in these naturally developed cyanobacteria strains could benefit both industry and the environment, contributing to the production of useful carbon-based products or facilitating carbon sinking to the ocean’s floor. While enhancements could further improve these microbes, leveraging billions of years of evolution represents a significant advancement in the urgent goal of combating climate change,” noted George Church, a professor at HMS and MIT. “However, it is essential to develop necessary safety measures before proceeding with such initiatives; our lab is also involved in studying bio-containment methods to oversee these experiments.”
“The Wyss Institute was founded on the principle that Nature is the richest source of innovative ideas, and that emulating its mechanisms can lead to significant progress. I commend this team for venturing beyond laboratory settings to seek innovative solutions in Nature’s creations. This is an excellent demonstration of our Sustainable Futures Initiative’s aim to tackle climate change in imaginative ways—one of the greatest challenges we face today,” remarked Don Ingber, M.D., Ph.D., Wyss Founding Director and professor at HMS and Harvard’s School of Engineering and Applied Sciences.
Other contributors to this study include Tzu-Chieh Tang, Isabella Goodchild-Michelman, Krista Ryon, James Henriksen, Theodore Chavkin, Yanqi Wu, Teemu Miettinen, Stefanie Van Wychen, Lukas Dahlin, Davide Spatafora, Gabriele Turco, Michael Guarnieri, Scott Manalis, John Kowitz, Raja Dhir, Paola Quatrini, Christopher Mason, and Marco Milazzo.
This research received support from the U.S. Department of Energy (DOE) under grant no. DE-FG02-02ER63445 and the National Science Foundation (NSF) award no. MCB-2037995, in addition to financial backing from SeedLabs, the WorldQuant Foundation, the Scientific Computing Unit (SCU) at Weill Cornell Medical College, and the International CO2 Natural Analogues (ICONA) Network.
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