Newly discovered cyanobacteria could help sequester carbon from oceans and factories
October 29, 2024
Strains specialized to live in high-CO2 oceanic environments have evolved traits that are useful for decarbonization and bioproduction
By Lindsay Brownell

(BOSTON) — An international coalition of researchers from the United States and Italy has discovered a novel strain of cyanobacteria, or algae, isolated from volcanic ocean vents that is especially adept at growing rapidly in the presence of CO2 and readily sinks in water, making it a prime candidate for biologically-based carbon sequestration projects and bioproduction of valuable commodities. This strain, nicknamed “Chonkus,” was found off the coast of the island of Vulcano in Sicily, Italy — an environment in which marine CO2 is abundant due to shallow volcanic vents. The discovery is described in a paper published today in Applied and Environmental Microbiology.

“Dissolved carbon is relatively dilute compared to all the other molecules in the ocean, and that limits the growth of photosynthetic organisms that live there. We decided to investigate what happens when you alleviate that limiting factor by going to a place with plenty of carbon, where some organisms could have evolved the ability to use it to galvanize their growth,” said co-corresponding author Max Schubert, Ph.D., who was a staff scientist at the Wyss Institute at Harvard University when the work was conducted and is now Lead Project Scientist at Align to Innovate. “This naturally occurring strain of cyanobacteria has several traits that could be useful to humans, including highly dense growth and a natural tendency to sink in water, making Chonkus a particularly interesting organism for future work on decarbonization and biomanufacturing.”

From the shallow sea to the lab bench
Schubert and fellow corresponding author Braden Tierney, Ph.D. first met as bench neighbors in the lab of Wyss Core Faculty member George Church, Ph.D. nine years ago, but didn’t start collaborating until both were later working at Harvard Medical School (HMS) in 2016. Schubert, a microbiologist who was interested in building tools for directed evolution of bacteria and their genomes, submitted a proposal to the HMS Consortium for Space Genetics’ 2019 Symposium on Climate Change to bring this work to cyanobacteria. He won the top prize, which funded his early forays into applying his tools to cyanobacteria to investigate their potential to help fix and sequester carbon.

Meanwhile, Tierney, who was then a postdoc co-advised by Schubert’s advisor Church, was sent a paper by a friend about shallow seeps – areas on the ocean floor where gasses seep into the water but are shallow enough to receive sunlight – and realized that there might be photosynthetic microbes living in those environments that had evolved to be adept at capturing dissolved CO2 from the water. He made connections with Marco Milazzo, Ph.D. and Paola Quatrini, Ph.D., both professors at the University of Palermo in Sicily, who were actively studying nearby, accessible shallow seeps. Tierney secured funding for a collecting expedition from SeedLabs, and reached out to Schubert for help understanding and working with the cyanobacteria that could be present in that environment.

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