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    MIT chemists boost the efficiency of a key enzyme in photosynthesis

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    During photosynthesis, an enzyme called rubisco catalyzes a key reaction — the incorporation of carbon dioxide into organic compounds to create sugars. However, rubisco, which is believed to be the most abundant enzyme on Earth, is very inefficient compared to the other enzymes involved in photosynthesis.MIT chemists have now shown that they can greatly enhance a version of rubisco found in bacteria from a low-oxygen environment. Using a process known as directed evolution, they identified mutations that could boost rubisco’s catalytic efficiency by up to 25 percent.The researchers now plan to apply their technique to forms of rubisco that could be used in plants to help boost their rates of photosynthesis, which could potentially improve crop yields.“This is, I think, a compelling demonstration of successful improvement of a rubisco’s enzymatic properties, holding out a lot of hope for engineering other forms of rubisco,” says Matthew Shoulders, the Class of 1942 Professor of Chemistry at MIT.Shoulders and Robert Wilson, a research scientist in the Department of Chemistry, are the senior authors of the new study, which appears this week in the Proceedings of the National Academy of Sciences. MIT graduate student Julie McDonald is the paper’s lead author.Evolution of efficiencyWhen plants or photosynthetic bacteria absorb energy from the sun, they first convert it into energy-storing molecules such as ATP. In the next phase of photosynthesis, cells use that energy to transform a molecule known as ribulose bisphosphate into glucose, which requires several additional reactions. Rubisco catalyzes the first of those reactions, known as carboxylation. During that reaction, carbon from CO2 is added to ribulose bisphosphate.Compared to the other enzymes involved in photosynthesis, rubisco is very slow, catalyzing only one to 10 reactions per second. Additionally, rubisco can also interact with oxygen, leading to a competing reaction that incorporates oxygen instead of carbon — a process that wastes some of the energy absorbed from sunlight.“For protein engineers, that’s a really attractive set of problems because those traits seem like things that you could hopefully make better by making changes to the enzyme’s amino acid sequence,” McDonald says.Previous research has led to improvement in rubisco’s stability and solubility, which resulted in small gains in enzyme efficiency. Most of those studies used directed evolution — a technique in which a naturally occurring protein is randomly mutated and then screened for the emergence of new, desirable features.This process is usually done using error-prone PCR, a technique that first generates mutations in vitro (outside of the cell), typically introducing only one or two mutations in the target gene. In past studies on rubisco, this library of mutations was then introduced into bacteria that grow at a rate relative to rubisco activity. Limitations in error-prone PCR and in the efficiency of introducing new genes restrict the total number of mutations that can be generated and screened using this approach. Manual mutagenesis and selection steps also add more time to the process over multiple rounds of evolution.The MIT team instead used a newer mutagenesis technique that the Shoulders Lab previously developed, called MutaT7. This technique allows the researchers to perform both mutagenesis and screening in living cells, which dramatically speeds up the process. Their technique also enables them to mutate the target gene at a higher rate.“Our continuous directed evolution technique allows you to look at a lot more mutations in the enzyme than has been done in the past,” McDonald says.Better rubiscoFor this study, the researchers began with a version of rubisco, isolated from a family of semi-anaerobic bacteria known as Gallionellaceae, that is one of the fastest rubisco found in nature. During the directed evolution experiments, which were conducted in E. coli, the researchers kept the microbes in an environment with atmospheric levels of oxygen, creating evolutionary pressure to adapt to oxygen.After six rounds of directed evolution, the researchers identified three different mutations that improved the rubisco’s resistance to oxygen. Each of these mutations are located near the enzyme’s active site (where it performs carboxylation or oxygenation). The researchers believe that these mutations improve the enzyme’s ability to preferentially interact with carbon dioxide over oxygen, which leads to an overall increase in carboxylation efficiency.“The underlying question here is: Can you alter and improve the kinetic properties of rubisco to operate better in environments where you want it to operate better?” Shoulders says. “What changed through the directed evolution process was that rubisco began to like to react with oxygen less. That allows this rubisco to function well in an oxygen-rich environment, where normally it would constantly get distracted and react with oxygen, which you don’t want it to do.”In ongoing work, the researchers are applying this approach to other forms of rubisco, including rubisco from plants. Plants are believed to lose about 30 percent of the energy from the sunlight they absorb through a process called photorespiration, which occurs when rubisco acts on oxygen instead of carbon dioxide.“This really opens the door to a lot of exciting new research, and it’s a step beyond the types of engineering that have dominated rubisco engineering in the past,” Wilson says. “There are definite benefits to agricultural productivity that could be leveraged through a better rubisco.”The research was funded, in part, by the National Science Foundation, the National Institutes of Health, an Abdul Latif Jameel Water and Food Systems Lab Grand Challenge grant, and a Martin Family Society Fellowship for Sustainability. More

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      in Environment

      Island rivers carve passageways through coral reefs

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      Volcanic islands, such as the islands of Hawaii and the Caribbean, are surrounded by coral reefs that encircle an island in a labyrinthine, living ring. A coral reef is punctured at points by reef passes — wide channels that cut through the coral and serve as conduits for ocean water and nutrients to filter in and out. These watery passageways provide circulation throughout a reef, helping to maintain the health of corals by flushing out freshwater and transporting key nutrients.Now, MIT scientists have found that reef passes are shaped by island rivers. In a study appearing today in the journal Geophysical Research Letters, the team shows that the locations of reef passes along coral reefs line up with where rivers funnel out from an island’s coast.Their findings provide the first quantitative evidence of rivers forming reef passes.  Scientists and explorers had speculated that this may be the case: Where a river on a volcanic island meets the coast, the freshwater and sediment it carries flows toward the reef, where a strong enough flow can tunnel into the surrounding coral. This idea has been proposed from time to time but never quantitatively tested, until now.“The results of this study help us to understand how the health of coral reefs depends on the islands they surround,” says study author Taylor Perron, the Cecil and Ida Green Professor of Earth, Atmospheric and Planetary Sciences at MIT.“A lot of discussion around rivers and their impact on reefs today has been negative because of human impact and the effects of agricultural practices,” adds lead author Megan Gillen, a graduate student in the MIT-WHOI Joint Program in Oceanography. “This study shows the potential long-term benefits rivers can have on reefs, which I hope reshapes the paradigm and highlights the natural state of rivers interacting with reefs.”The study’s other co-author is Andrew Ashton of the Woods Hole Oceanographic Institution.Drawing the linesThe new study is based on the team’s analysis of the Society Islands, a chain of islands in the South Pacific Ocean that includes Tahiti and Bora Bora. Gillen, who joined the MIT-WHOI program in 2020, was interested in exploring connections between coral reefs and the islands they surround. With limited options for on-site work during the Covid-19 pandemic, she and Perron looked to see what they could learn through satellite images and maps of island topography. They did a quick search using Google Earth and zeroed in on the Society Islands for their uniquely visible reef and island features.“The islands in this chain have these iconic, beautiful reefs, and we kept noticing these reef passes that seemed to align with deeply embayed portions of the coastline,” Gillen says. “We started asking ourselves, is there a correlation here?”Viewed from above, the coral reefs that circle some islands bear what look to be notches, like cracks that run straight through a ring. These breaks in the coral are reef passes — large channels that run tens of meters deep and can be wide enough for some boats to pass through. On first look, Gillen noticed that the most obvious reef passes seemed to line up with flooded river valleys — depressions in the coastline that have been eroded over time by island rivers that flow toward the ocean. She wondered whether and to what extent island rivers might shape reef passes.“People have examined the flow through reef passes to understand how ocean waves and seawater circulate in and out of lagoons, but there have been no claims of how these passes are formed,” Gillen says. “Reef pass formation has been mentioned infrequently in the literature, and people haven’t explored it in depth.”Reefs unraveledTo get a detailed view of the topography in and around the Society Islands, the team used data from the NASA Shuttle Radar Topography Mission — two radar antennae that flew aboard the space shuttle in 1999 and measured the topography across 80 percent of the Earth’s surface.The researchers used the mission’s topographic data in the Society Islands to create a map of every drainage basin along the coast of each island, to get an idea of where major rivers flow or once flowed. They also marked the locations of every reef pass in the surrounding coral reefs. They then essentially “unraveled” each island’s coastline and reef into a straight line, and compared the locations of basins versus reef passes.“Looking at the unwrapped shorelines, we find a significant correlation in the spatial relationship between these big river basins and where the passes line up,” Gillen says. “So we can say that statistically, the alignment of reef passes and large rivers does not seem random. The big rivers have a role in forming passes.”As for how rivers shape the coral conduits, the team has two ideas, which they call, respectively, reef incision and reef encroachment. In reef incision, they propose that reef passes can form in times when the sea level is relatively low, such that the reef is exposed above the sea surface and a river can flow directly over the reef. The water and sediment carried by the river can then erode the coral, progressively carving a path through the reef.When sea level is relatively higher, the team suspects a reef pass can still form, through reef encroachment. Coral reefs naturally live close to the water surface, where there is light and opportunity for photosynthesis. When sea levels rise, corals naturally grow upward and inward toward an island, to try to “catch up” to the water line.“Reefs migrate toward the islands as sea levels rise, trying to keep pace with changing average sea level,” Gillen says.However, part of the encroaching reef can end up in old river channels that were previously carved out by large rivers and that are lower than the rest of the island coastline. The corals in these river beds end up deeper than light can extend into the water column, and inevitably drown, leaving a gap in the form of a reef pass.“We don’t think it’s an either/or situation,” Gillen says. “Reef incision occurs when sea levels fall, and reef encroachment happens when sea levels rise. Both mechanisms, occurring over dozens of cycles of sea-level rise and island evolution, are likely responsible for the formation and maintenance of reef passes over time.”The team also looked to see whether there were differences in reef passes in older versus younger islands. They observed that younger islands were surrounded by more reef passes that were spaced closer together, versus older islands that had fewer reef passes that were farther apart.As islands age, they subside, or sink, into the ocean, which reduces the amount of land that funnels rainwater into rivers. Eventually, rivers are too weak to keep the reef passes open, at which point, the ocean likely takes over, and incoming waves could act to close up some passes.Gillen is exploring ideas for how rivers, or river-like flow, can be engineered to create paths through coral reefs in ways that would promote circulation and benefit reef health.“Part of me wonders: If you had a more persistent flow, in places where you don’t naturally have rivers interacting with the reef, could that potentially be a way to increase health, by incorporating that river component back into the reef system?” Gillen says. “That’s something we’re thinking about.”This research was supported, in part, by the WHOI Watson and Von Damm fellowships. More

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      in Environment

      When Earth iced over, early life may have sheltered in meltwater ponds

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      When the Earth froze over, where did life shelter? MIT scientists say one refuge may have been pools of melted ice that dotted the planet’s icy surface.In a study appearing today in Nature Communications, the researchers report that 635 million to 720 million years ago, during periods known as “Snowball Earth,” when much of the planet was covered in ice, some of our ancient cellular ancestors could have waited things out in meltwater ponds.The scientists found that eukaryotes — complex cellular lifeforms that eventually evolved into the diverse multicellular life we see today — could have survived the global freeze by living in shallow pools of water. These small, watery oases may have persisted atop relatively shallow ice sheets present in equatorial regions. There, the ice surface could accumulate dark-colored dust and debris from below, which enhanced its ability to melt into pools. At temperatures hovering around 0 degrees Celsius, the resulting meltwater ponds could have served as habitable environments for certain forms of early complex life.The team drew its conclusions based on an analysis of modern-day meltwater ponds. Today in Antarctica, small pools of melted ice can be found along the margins of ice sheets. The conditions along these polar ice sheets are similar to what likely existed along ice sheets near the equator during Snowball Earth.The researchers analyzed samples from a variety of meltwater ponds located on the McMurdo Ice Shelf in an area that was first described by members of Robert Falcon Scott’s 1903 expedition as “dirty ice.” The MIT researchers discovered clear signatures of eukaryotic life in every pond. The communities of eukaryotes varied from pond to pond, revealing a surprising diversity of life across the setting. The team also found that salinity plays a key role in the kind of life a pond can host: Ponds that were more brackish or salty had more similar eukaryotic communities, which differed from those in ponds with fresher waters.“We’ve shown that meltwater ponds are valid candidates for where early eukaryotes could have sheltered during these planet-wide glaciation events,” says lead author Fatima Husain, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “This shows us that diversity is present and possible in these sorts of settings. It’s really a story of life’s resilience.”The study’s MIT co-authors include Schlumberger Professor of Geobiology Roger Summons and former postdoc Thomas Evans, along with Jasmin Millar of Cardiff University, Anne Jungblut at the Natural History Museum in London, and Ian Hawes of the University of Waikato in New Zealand.Polar plunge“Snowball Earth” is the colloquial term for periods of time in Earth history during which the planet iced over. It is often used as a reference to the two consecutive, multi-million-year glaciation events which took place during the Cryogenian Period, which geologists refer to as the time between 635 and 720 million years ago. Whether the Earth was more of a hardened snowball or a softer “slushball” is still up for debate. But scientists are certain of one thing: Most of the planet was plunged into a deep freeze, with average global temperatures of minus 50 degrees Celsius. The question has been: How and where did life survive?“We’re interested in understanding the foundations of complex life on Earth. We see evidence for eukaryotes before and after the Cryogenian in the fossil record, but we largely lack direct evidence of where they may have lived during,” Husain says. “The great part of this mystery is, we know life survived. We’re just trying to understand how and where.”There are a number of ideas for where organisms could have sheltered during Snowball Earth, including in certain patches of the open ocean (if such environments existed), in and around deep-sea hydrothermal vents, and under ice sheets. In considering meltwater ponds, Husain and her colleagues pursued the hypothesis that surface ice meltwaters may also have been capable of supporting early eukaryotic life at the time.“There are many hypotheses for where life could have survived and sheltered during the Cryogenian, but we don’t have excellent analogs for all of them,” Husain notes. “Above-ice meltwater ponds occur on Earth today and are accessible, giving us the opportunity to really focus in on the eukaryotes which live in these environments.”Small pond, big lifeFor their new study, the researchers analyzed samples taken from meltwater ponds in Antarctica. In 2018, Summons and colleagues from New Zealand traveled to a region of the McMurdo Ice Shelf in East Antarctica, known to host small ponds of melted ice, each just a few feet deep and a few meters wide. There, water freezes all the way to the seafloor, in the process trapping dark-colored sediments and marine organisms. Wind-driven loss of ice from the surface creates a sort of conveyer belt that brings this trapped debris to the surface over time, where it absorbs the sun’s warmth, causing ice to melt, while surrounding debris-free ice reflects incoming sunlight, resulting in the formation of shallow meltwater ponds.The bottom of each pond is lined with mats of microbes that have built up over years to form layers of sticky cellular communities.“These mats can be a few centimeters thick, colorful, and they can be very clearly layered,” Husain says.These microbial mats are made up of cyanobacteria, prokaryotic, single-celled photosynthetic organisms that lack a cell nucleus or other organelles. While these ancient microbes are known to survive within some of the the harshest environments on Earth including meltwater ponds, the researchers wanted to know whether eukaryotes — complex organisms that evolved a cell nucleus and other membrane bound organelles — could also weather similarly challenging circumstances. Answering this question would take more than a microscope, as the defining characteristics of the microscopic eukaryotes present among the microbial mats are too subtle to distinguish by eye.To characterize the eukaryotes, the team analyzed the mats for specific lipids they make called sterols, as well as genetic components called ribosomal ribonucleic acid (rRNA), both of which can be used to identify organisms with varying degrees of specificity. These two independent sets of analyses provided complementary fingerprints for certain eukaryotic groups. As part of the team’s lipid research, they found many sterols and rRNA genes closely associated with specific types of algae, protists, and microscopic animals among the microbial mats. The researchers were able to assess the types and relative abundance of lipids and rRNA genes from pond to pond, and found the ponds hosted a surprising diversity of eukaryotic life.“No two ponds were alike,” Husain says. “There are repeating casts of characters, but they’re present in different abundances. And we found diverse assemblages of eukaryotes from all the major groups in all the ponds studied. These eukaryotes are the descendants of the eukaryotes that survived the Snowball Earth. This really highlights that meltwater ponds during Snowball Earth could have served as above-ice oases that nurtured the eukaryotic life that enabled the diversification and proliferation of complex life — including us — later on.”This research was supported, in part, by the NASA Exobiology Program, the Simons Collaboration on the Origins of Life, and a MISTI grant from MIT-New Zealand. More

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      in Environment

      After more than a decade of successes, ESI’s work will spread out across the Institute

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      MIT’s Environmental Solutions Initiative (ESI), a pioneering cross-disciplinary body that helped give a major boost to sustainability and solutions to climate change at MIT, will close as a separate entity at the end of June. But that’s far from the end for its wide-ranging work, which will go forward under different auspices. Many of its key functions will become part of MIT’s recently launched Climate Project. John Fernandez, head of ESI for nearly a decade, will return to the School of Architecture and Planning, where some of ESI’s important work will continue as part of a new interdisciplinary lab.When the ideas that led to the founding of MIT’s Environmental Solutions Initiative first began to be discussed, its founders recall, there was already a great deal of work happening at MIT relating to climate change and sustainability. As Professor John Sterman of the MIT Sloan School of Management puts it, “there was a lot going on, but it wasn’t integrated. So the whole added up to less than the sum of its parts.”ESI was founded in 2014 to help fill that coordinating role, and in the years since it has accomplished a wide range of significant milestones in research, education, and communication about sustainable solutions in a wide range of areas. Its founding director, Professor Susan Solomon, helmed it for its first year, and then handed the leadership to Fernandez, who has led it since 2015.“There wasn’t much of an ecosystem [on sustainability] back then,” Solomon recalls. But with the help of ESI and some other entities, that ecosystem has blossomed. She says that Fernandez “has nurtured some incredible things under ESI,” including work on nature-based climate solutions, and also other areas such as sustainable mining, and reduction of plastics in the environment.Desiree Plata, director of MIT’s Climate and Sustainability Consortium and associate professor of civil and environmental engineering, says that one key achievement of the initiative has been in “communication with the external world, to help take really complex systems and topics and put them in not just plain-speak, but something that’s scientifically rigorous and defensible, for the outside world to consume.”In particular, ESI has created three very successful products, which continue under the auspices of the Climate Project. These include the popular TIL Climate Podcast, the Webby Award-winning Climate Portal website, and the online climate primer developed with Professor Kerry Emanuel. “These are some of the most frequented websites at MIT,” Plata says, and “the impact of this work on the global knowledge base cannot be overstated.”Fernandez says that ESI has played a significant part in helping to catalyze what has become “a rich institutional landscape of work in sustainability and climate change” at MIT. He emphasizes three major areas where he feels the ESI has been able to have the most impact: engaging the MIT community, initiating and stewarding critical environmental research, and catalyzing efforts to promote sustainability as fundamental to the mission of a research university.Engagement of the MIT community, he says, began with two programs: a research seed grant program and the creation of MIT’s undergraduate minor in environment and sustainability, launched in 2017.ESI also created a Rapid Response Group, which gave students a chance to work on real-world projects with external partners, including government agencies, community groups, nongovernmental organizations, and businesses. In the process, they often learned why dealing with environmental challenges in the real world takes so much longer than they might have thought, he says, and that a challenge that “seemed fairly straightforward at the outset turned out to be more complex and nuanced than expected.”The second major area, initiating and stewarding environmental research, grew into a set of six specific program areas: natural climate solutions, mining, cities and climate change, plastics and the environment, arts and climate, and climate justice.These efforts included collaborations with a Nobel Peace Prize laureate, three successive presidential administrations from Colombia, and members of communities affected by climate change, including coal miners, indigenous groups, various cities, companies, the U.N., many agencies — and the popular musical group Coldplay, which has pledged to work toward climate neutrality for its performances. “It was the role that the ESI played as a host and steward of these research programs that may serve as a key element of our legacy,” Fernandez says.The third broad area, he says, “is the idea that the ESI as an entity at MIT would catalyze this movement of a research university toward sustainability as a core priority.” While MIT was founded to be an academic partner to the industrialization of the world, “aren’t we in a different world now? The kind of massive infrastructure planning and investment and construction that needs to happen to decarbonize the energy system is maybe the largest industrialization effort ever undertaken. Even more than in the recent past, the set of priorities driving this have to do with sustainable development.”Overall, Fernandez says, “we did everything we could to infuse the Institute in its teaching and research activities with the idea that the world is now in dire need of sustainable solutions.”Fernandez “has nurtured some incredible things under ESI,” Solomon says. “It’s been a very strong and useful program, both for education and research.” But it is appropriate at this time to distribute its projects to other venues, she says. “We do now have a major thrust in the Climate Project, and you don’t want to have redundancies and overlaps between the two.”Fernandez says “one of the missions of the Climate Project is really acting to coalesce and aggregate lots of work around MIT.” Now, with the Climate Project itself, along with the Climate Policy Center and the Center for Sustainability Science and Strategy, it makes more sense for ESI’s climate-related projects to be integrated into these new entities, and other projects that are less directly connected to climate to take their places in various appropriate departments or labs, he says.“We did enough with ESI that we made it possible for these other centers to really flourish,” he says. “And in that sense, we played our role.”As of June 1, Fernandez has returned to his role as professor of architecture and urbanism and building technology in the School of Architecture and Planning, where he directs the Urban Metabolism Group. He will also be starting up a new group called Environment ResearchAction (ERA) to continue ESI work in cities, nature, and artificial intelligence.  More

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      in Energy

      Decarbonizing steel is as tough as steel

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      The long-term aspirational goal of the Paris Agreement on climate change is to cap global warming at 1.5 degrees Celsius above preindustrial levels, and thereby reduce the frequency and severity of floods, droughts, wildfires, and other extreme weather events. Achieving that goal will require a massive reduction in global carbon dioxide (CO2) emissions across all economic sectors. A major roadblock, however, could be the industrial sector, which accounts for roughly 25 percent of global energy- and process-related CO2 emissions — particularly within the iron and steel sector, industry’s largest emitter of CO2.Iron and steel production now relies heavily on fossil fuels (coal or natural gas) for heat, converting iron ore to iron, and making steel strong. Steelmaking could be decarbonized by a combination of several methods, including carbon capture technology, the use of low- or zero-carbon fuels, and increased use of recycled steel. Now a new study in the Journal of Cleaner Production systematically explores the viability of different iron-and-steel decarbonization strategies.Today’s strategy menu includes improving energy efficiency, switching fuels and technologies, using more scrap steel, and reducing demand. Using the MIT Economic Projection and Policy Analysis model, a multi-sector, multi-region model of the world economy, researchers at MIT, the University of Illinois at Urbana-Champaign, and ExxonMobil Technology and Engineering Co. evaluate the decarbonization potential of replacing coal-based production processes with electric arc furnaces (EAF), along with either scrap steel or “direct reduced iron” (DRI), which is fueled by natural gas with carbon capture and storage (NG CCS DRI-EAF) or by hydrogen (H2 DRI-EAF).Under a global climate mitigation scenario aligned with the 1.5 C climate goal, these advanced steelmaking technologies could result in deep decarbonization of the iron and steel sector by 2050, as long as technology costs are low enough to enable large-scale deployment. Higher costs would favor the replacement of coal with electricity and natural gas, greater use of scrap steel, and reduced demand, resulting in a more-than-50-percent reduction in emissions relative to current levels. Lower technology costs would enable massive deployment of NG CCS DRI-EAF or H2 DRI-EAF, reducing emissions by up to 75 percent.Even without adoption of these advanced technologies, the iron-and-steel sector could significantly reduce its CO2 emissions intensity (how much CO2 is released per unit of production) with existing steelmaking technologies, primarily by replacing coal with gas and electricity (especially if it is generated by renewable energy sources), using more scrap steel, and implementing energy efficiency measures.“The iron and steel industry needs to combine several strategies to substantially reduce its emissions by mid-century, including an increase in recycling, but investing in cost reductions in hydrogen pathways and carbon capture and sequestration will enable even deeper emissions mitigation in the sector,” says study supervising author Sergey Paltsev, deputy director of the MIT Center for Sustainability Science and Strategy (MIT CS3) and a senior research scientist at the MIT Energy Initiative (MITEI).This study was supported by MIT CS3 and ExxonMobil through its membership in MITEI. More

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      in Energy

      “Each of us holds a piece of the solution”

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      MIT has an unparalleled history of bringing together interdisciplinary teams to solve pressing problems — think of the development of radar during World War II, or leading the international coalition that cracked the code of the human genome — but the challenge of climate change could demand a scale of collaboration unlike any that’s come before at MIT.“Solving climate change is not just about new technologies or better models. It’s about forging new partnerships across campus and beyond — between scientists and economists, between architects and data scientists, between policymakers and physicists, between anthropologists and engineers, and more,” MIT Vice President for Energy and Climate Evelyn Wang told an energetic crowd of faculty, students, and staff on May 6. “Each of us holds a piece of the solution — but only together can we see the whole.”Undeterred by heavy rain, approximately 300 campus community members filled the atrium in the Tina and Hamid Moghadam Building (Building 55) for a spring gathering hosted by Wang and the Climate Project at MIT. The initiative seeks to direct the full strength of MIT to address climate change, which Wang described as one of the defining challenges of this moment in history — and one of its greatest opportunities.“It calls on us to rethink how we power our world, how we build, how we live — and how we work together,” Wang said. “And there is no better place than MIT to lead this kind of bold, integrated effort. Our culture of curiosity, rigor, and relentless experimentation makes us uniquely suited to cross boundaries — to break down silos and build something new.”The Climate Project is organized around six missions, thematic areas in which MIT aims to make significant impact, ranging from decarbonizing industry to new policy approaches to designing resilient cities. The faculty leaders of these missions posed challenges to the crowd before circulating among the crowd to share their perspectives and to discuss community questions and ideas.Wang and the Climate Project team were joined by a number of research groups, startups, and MIT offices conducting relevant work today on issues related to energy and climate. For example, the MIT Office of Sustainability showcased efforts to use the MIT campus as a living laboratory; MIT spinouts such as Forma Systems, which is developing high-performance, low-carbon building systems, and Addis Energy, which envisions using the earth as a reactor to produce clean ammonia, presented their technologies; and visitors learned about current projects in MIT labs, including DebunkBot, an artificial intelligence-powered chatbot that can persuade people to shift their attitudes about conspiracies, developed by David Rand, the Erwin H. Schell Professor at the MIT Sloan School of Management.Benedetto Marelli, an associate professor in the Department of Civil and Environmental Engineering who leads the Wild Cards Mission, said the energy and enthusiasm that filled the room was inspiring — but that the individual conversations were equally valuable.“I was especially pleased to see so many students come out. I also spoke with other faculty, talked to staff from across the Institute, and met representatives of external companies interested in collaborating with MIT,” Marelli said. “You could see connections being made all around the room, which is exactly what we need as we build momentum for the Climate Project.” More

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      in Security

      Universal nanosensor unlocks the secrets to plant growth

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      Researchers from the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) interdisciplinary research group within the Singapore-MIT Alliance for Research and Technology have developed the world’s first near-infrared fluorescent nanosensor capable of real-time, nondestructive, and species-agnostic detection of indole-3-acetic acid (IAA) — the primary bioactive auxin hormone that controls the way plants develop, grow, and respond to stress.Auxins, particularly IAA, play a central role in regulating key plant processes such as cell division, elongation, root and shoot development, and response to environmental cues like light, heat, and drought. External factors like light affect how auxin moves within the plant, temperature influences how much is produced, and a lack of water can disrupt hormone balance. When plants cannot effectively regulate auxins, they may not grow well, adapt to changing conditions, or produce as much food. Existing IAA detection methods, such as liquid chromatography, require taking plant samples from the plant — which harms or removes part of it. Conventional methods also measure the effects of IAA rather than detecting it directly, and cannot be used universally across different plant types. In addition, since IAA are small molecules that cannot be easily tracked in real time, biosensors that contain fluorescent proteins need to be inserted into the plant’s genome to measure auxin, making it emit a fluorescent signal for live imaging.SMART’s newly developed nanosensor enables direct, real-time tracking of auxin levels in living plants with high precision. The sensor uses near infrared imaging to monitor IAA fluctuations non-invasively across tissues like leaves, roots, and cotyledons, and it is capable of bypassing chlorophyll interference to ensure highly reliable readings even in densely pigmented tissues. The technology does not require genetic modification and can be integrated with existing agricultural systems — offering a scalable precision tool to advance both crop optimization and fundamental plant physiology research. By providing real-time, precise measurements of auxin, the sensor empowers farmers with earlier and more accurate insights into plant health. With these insights and comprehensive data, farmers can make smarter, data-driven decisions on irrigation, nutrient delivery, and pruning, tailored to the plant’s actual needs — ultimately improving crop growth, boosting stress resilience, and increasing yields.“We need new technologies to address the problems of food insecurity and climate change worldwide. Auxin is a central growth signal within living plants, and this work gives us a way to tap it to give new information to farmers and researchers,” says Michael Strano, co-lead principal investigator at DiSTAP, Carbon P. Dubbs Professor of Chemical Engineering at MIT, and co-corresponding author of the paper. “The applications are many, including early detection of plant stress, allowing for timely interventions to safeguard crops. For urban and indoor farms, where light, water, and nutrients are already tightly controlled, this sensor can be a valuable tool in fine-tuning growth conditions with even greater precision to optimize yield and sustainability.”The research team documented the nanosensor’s development in a paper titled, “A Near-Infrared Fluorescent Nanosensor for Direct and Real-Time Measurement of Indole-3-Acetic Acid in Plants,” published in the journal ACS Nano. The sensor comprises single-walled carbon nanotubes wrapped in a specially designed polymer, which enables it to detect IAA through changes in near infrared fluorescence intensity. Successfully tested across multiple species, including Arabidopsis, Nicotiana benthamiana, choy sum, and spinach, the nanosensor can map IAA responses under various environmental conditions such as shade, low light, and heat stress. “This sensor builds on DiSTAP’s ongoing work in nanotechnology and the CoPhMoRe technique, which has already been used to develop other sensors that can detect important plant compounds such as gibberellins and hydrogen peroxide. By adapting this approach for IAA, we’re adding to our inventory of novel, precise, and nondestructive tools for monitoring plant health. Eventually, these sensors can be multiplexed, or combined, to monitor a spectrum of plant growth markers for more complete insights into plant physiology,” says Duc Thinh Khong, research scientist at DiSTAP and co-first author of the paper.“This small but mighty nanosensor tackles a long-standing challenge in agriculture: the need for a universal, real-time, and noninvasive tool to monitor plant health across various species. Our collaborative achievement not only empowers researchers and farmers to optimize growth conditions and improve crop yield and resilience, but also advances our scientific understanding of hormone pathways and plant-environment interactions,” says In-Cheol Jang, senior principal investigator at TLL, principal investigator at DiSTAP, and co-corresponding author of the paper.Looking ahead, the research team is looking to combine multiple sensing platforms to simultaneously detect IAA and its related metabolites to create a comprehensive hormone signaling profile, offering deeper insights into plant stress responses and enhancing precision agriculture. They are also working on using microneedles for highly localized, tissue-specific sensing, and collaborating with industrial urban farming partners to translate the technology into practical, field-ready solutions. The research was carried out by SMART, and supported by the National Research Foundation of Singapore under its Campus for Research Excellence And Technological Enterprise program. More

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      New facility to accelerate materials solutions for fusion energy

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      Fusion energy has the potential to enable the energy transition from fossil fuels, enhance domestic energy security, and power artificial intelligence. Private companies have already invested more than $8 billion to develop commercial fusion and seize the opportunities it offers. An urgent challenge, however, is the discovery and evaluation of cost-effective materials that can withstand extreme conditions for extended periods, including 150-million-degree plasmas and intense particle bombardment.To meet this challenge, MIT’s Plasma Science and Fusion Center (PSFC) has launched the Schmidt Laboratory for Materials in Nuclear Technologies, or LMNT (pronounced “element”). Backed by a philanthropic consortium led by Eric and Wendy Schmidt, LMNT is designed to speed up the discovery and selection of materials for a variety of fusion power plant components. By drawing on MIT’s expertise in fusion and materials science, repurposing existing research infrastructure, and tapping into its close collaborations with leading private fusion companies, the PSFC aims to drive rapid progress in the materials that are necessary for commercializing fusion energy on rapid timescales. LMNT will also help develop and assess materials for nuclear power plants, next-generation particle physics experiments, and other science and industry applications.Zachary Hartwig, head of LMNT and an associate professor in the Department of Nuclear Science and Engineering (NSE), says, “We need technologies today that will rapidly develop and test materials to support the commercialization of fusion energy. LMNT’s mission includes discovery science but seeks to go further, ultimately helping select the materials that will be used to build fusion power plants in the coming years.”A different approach to fusion materialsFor decades, researchers have worked to understand how materials behave under fusion conditions using methods like exposing test specimens to low-energy particle beams, or placing them in the core of nuclear fission reactors. These approaches, however, have significant limitations. Low-energy particle beams only irradiate the thinnest surface layer of materials, while fission reactor irradiation doesn’t accurately replicate the mechanism by which fusion damages materials. Fission irradiation is also an expensive, multiyear process that requires specialized facilities.To overcome these obstacles, researchers at MIT and peer institutions are exploring the use of energetic beams of protons to simulate the damage materials undergo in fusion environments. Proton beams can be tuned to match the damage expected in fusion power plants, and protons penetrate deep enough into test samples to provide insights into how exposure can affect structural integrity. They also offer the advantage of speed: first, intense proton beams can rapidly damage dozens of material samples at once, allowing researchers to test them in days, rather than years. Second, high-energy proton beams can be generated with a type of particle accelerator known as a cyclotron commonly used in the health-care industry. As a result, LMNT will be built around a cost-effective, off-the-shelf cyclotron that is easy to obtain and highly reliable.LMNT will surround its cyclotron with four experimental areas dedicated to materials science research. The lab is taking shape inside the large shielded concrete vault at PSFC that once housed the Alcator C-Mod tokamak, a record-setting fusion experiment that ran at the PSFC from 1992 to 2016. By repurposing C-Mod’s former space, the center is skipping the need for extensive, costly new construction and accelerating the research timeline significantly. The PSFC’s veteran team — who have led major projects like the Alcator tokamaks and advanced high-temperature superconducting magnet development — are overseeing the facilities design, construction, and operation, ensuring LMNT moves quickly from concept to reality. The PSFC expects to receive the cyclotron by the end of 2025, with experimental operations starting in early 2026.“LMNT is the start of a new era of fusion research at MIT, one where we seek to tackle the most complex fusion technology challenges on timescales commensurate with the urgency of the problem we face: the energy transition,” says Nuno Loureiro, director of the PSFC, a professor of nuclear science and engineering, and the Herman Feshbach Professor of Physics. “It’s ambitious, bold, and critical — and that’s exactly why we do it.”“What’s exciting about this project is that it aligns the resources we have today — substantial research infrastructure, off-the-shelf technologies, and MIT expertise — to address the key resource we lack in tackling climate change: time. Using the Schmidt Laboratory for Materials in Nuclear Technologies, MIT researchers advancing fusion energy, nuclear power, and other technologies critical to the future of energy will be able to act now and move fast,” says Elsa Olivetti, the Jerry McAfee Professor in Engineering and a mission director of MIT’s Climate Project.In addition to advancing research, LMNT will provide a platform for educating and training students in the increasingly important areas of fusion technology. LMNT’s location on MIT’s main campus gives students the opportunity to lead research projects and help manage facility operations. It also continues the hands-on approach to education that has defined the PSFC, reinforcing that direct experience in large-scale research is the best approach to create fusion scientists and engineers for the expanding fusion industry workforce.Benoit Forget, head of NSE and the Korea Electric Power Professor of Nuclear Engineering, notes, “This new laboratory will give nuclear science and engineering students access to a unique research capability that will help shape the future of both fusion and fission energy.”Accelerating progress on big challengesPhilanthropic support has helped LMNT leverage existing infrastructure and expertise to move from concept to facility in just one-and-a-half years — a fast timeline for establishing a major research project.“I’m just as excited about this research model as I am about the materials science. It shows how focused philanthropy and MIT’s strengths can come together to build something that’s transformational — a major new facility that helps researchers from the public and private sectors move fast on fusion materials,” emphasizes Hartwig.By utilizing this approach, the PSFC is executing a major public-private partnership in fusion energy, realizing a research model that the U.S. fusion community has only recently started to explore, and demonstrating the crucial role that universities can play in the acceleration of the materials and technology required for fusion energy.“Universities have long been at the forefront of tackling society’s biggest challenges, and the race to identify new forms of energy and address climate change demands bold, high-risk, high-reward approaches,” says Ian Waitz, MIT’s vice president for research. “LMNT is helping turn fusion energy from a long-term ambition into a near-term reality.” More

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      Shaping the future through systems thinking

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      Long before she stepped into a lab, Ananda Santos Figueiredo was stargazing in Brazil, captivated by the cosmos and feeding her curiosity of science through pop culture, books, and the internet. She was drawn to astrophysics for its blend of visual wonder and mathematics.Even as a child, Santos sensed her aspirations reaching beyond the boundaries of her hometown. “I’ve always been drawn to STEM,” she says. “I had this persistent feeling that I was meant to go somewhere else to learn more, explore, and do more.”Her parents saw their daughter’s ambitions as an opportunity to create a better future. The summer before her sophomore year of high school, her family moved from Brazil to Florida.  She recalls that moment as “a big leap of faith in something bigger and we had no idea how it would turn out.” She was certain of one thing: She wanted an education that was both technically rigorous and deeply expansive, one that would allow her to pursue all her passions.At MIT, she found exactly what she was seeking in a community and curriculum that matched her curiosity and ambition. “I’ve always associated MIT with something new and exciting that was grasping towards the very best we can achieve as humans,” Santos says, emphasizing the use of technology and science to significantly impact society. “It’s a place where people aren’t afraid to dream big and work hard to make it a reality.”As a first-generation college student, she carried the weight of financial stress and the uncertainty that comes with being the first in her family to navigate college in the U.S. But she found a sense of belonging in the MIT community. “Being a first-generation student helped me grow,” she says. “It inspired me to seek out opportunities and help support others too.”She channeled that energy into student government roles for the undergraduate residence halls. Through Dormitory Council (DormCon) and her dormitory, Simmons Hall, her voice could help shape life on campus. She began serving as reservations chair for her dormitory but ended up becoming president of the dormitory before being elected dining chair and vice president for DormCon. She’s worked to improve dining hall operations and has planned major community events like Simmons Hall’s 20th anniversary and DormCon’s inaugural Field Day.Now, a senior about to earn her bachelor’s degree, Santos says MIT’s motto, “mens et manus” — “mind and hand” — has deeply resonated with her from the start. “Learning here goes far beyond the classroom,” she says. “I’ve been surrounded by people who are passionate and purposeful. That energy is infectious. It’s changed how I see myself and what I believe is possible.”Charting her own courseInitially a physics major, Santos’ academic path took a turn after a transformative internship with the World Bank’s data science lab between her sophomore and junior years. There, she used her coding skills to study the impacts of heat waves in the Philippines. The experience opened her eyes to the role technology and data can play in improving lives and broadened her view of what a STEM career could look like.“I realized I didn’t want to just study the universe — I wanted to change it,” she says. “I wanted to join systems thinking with my interest in the humanities, to build a better world for people and communities.”When MIT launched a new major in climate system science and engineering (Course 1-12) in 2023, Santos was the first student to declare it. The interdisciplinary structure of the program, blending climate science, engineering, energy systems, and policy, gave her a framework to connect her technical skills to real-world sustainability challenges.She tailored her coursework to align with her passions and career goals, applying her physics background (now her minor) to understand problems in climate, energy, and sustainable systems. “One of the most powerful things about the major is the breadth,” she says. “Even classes that aren’t my primary focus have expanded how I think.”Hands-on fieldwork has been a cornerstone of her learning. During MIT’s Independent Activities Period (IAP), she studied climate impacts in Hawai’i in the IAP Course 1.091 (Traveling Research Environmental Experiences, or TREX). This year, she studied the design of sustainable polymer systems in Course 1.096/10.496 (Design of Sustainable Polymer Systems) under MISTI’s Global Classroom program. The IAP class brought her to the middle of the Amazon Rainforest to see what the future of plastic production could look like with products from the Amazon. “That experience was incredibly eye opening,” she explains. “It helped me build a bridge between my own background and the kind of problems that I want to solve in the future.”Santos also found enjoyment beyond labs and lectures. A member of the MIT Shakespeare Ensemble since her first year, she took to the stage in her final spring production of “Henry V,” performing as both the Chorus and Kate. “The ensemble’s collaborative spirit and the way it brings centuries-old texts to life has been transformative,” she adds.Her passion for the arts also intersected with her interest in the MIT Lecture Series Committee. She helped host a special screening of the film “Sing Sing,” in collaboration with MIT’s Educational Justice Institute (TEJI). That connection led her to enroll in a TEJI course, illustrating the surprising and meaningful ways that different parts of MIT’s ecosystem overlap. “It’s one of the beautiful things about MIT,” she says. “You stumble into experiences that deeply change you.”Throughout her time at MIT, the community of passionate, sustainability-focused individuals has been a major source of inspiration. She’s been actively involved with the MIT Office of Sustainability’s decarbonization initiatives and participated in the Climate and Sustainability Scholars Program.Santos acknowledges that working in sustainability can sometimes feel overwhelming. “Tackling the challenges of sustainability can be discouraging,” she says. “The urgency to create meaningful change in a short period of time can be intimidating. But being surrounded by people who are actively working on it is so much better than not working on it at all.”Looking ahead, she plans to pursue graduate studies in technology and policy, with aspirations to shape sustainable development, whether through academia, international organizations, or diplomacy.“The most fulfilling moments I’ve had at MIT are when I’m working on hard problems while also reflecting on who I want to be, what kind of future I want to help create, and how we can be better and kinder to each other,” she says. “That’s what excites me — solving real problems that matter.” More