MIT Chemists Advance Rubisco Efficiency to Enhance Photosynthesis

CAMBRIDGE, MA — Researchers at the Massachusetts Institute of Technology (MIT) have made significant advances in enhancing the efficiency of the enzyme ribulose bisphosphate carboxylase/oxygenase (rubisco), a critical component in the photosynthesis process. This breakthrough, announced on July 8, 2025, involves a novel approach using directed evolution to improve rubisco's catalytic performance by up to 25%, a move that holds promise for higher crop yields and improved agricultural productivity.

Rubisco is regarded as the most abundant enzyme on Earth, responsible for catalyzing the incorporation of carbon dioxide into organic compounds, ultimately facilitating the production of sugars in plants. However, its inefficiency has long been a challenge; it catalyzes only one to ten reactions per second and can also engage in a wasteful reaction with oxygen, leading to photorespiration, which diminishes the energy plants derive from sunlight. According to Dr. Matthew Shoulders, the Class of 1942 Professor of Chemistry at MIT and senior author of the study, "This is a compelling demonstration of successful improvement of rubisco's enzymatic properties, holding out a lot of hope for engineering other forms of rubisco."

The researchers, including lead author Julie McDonald, a graduate student at MIT, utilized a cutting-edge mutagenesis technique known as MutaT7, which allows for both mutagenesis and screening within living cells. This method significantly accelerates the process of identifying beneficial mutations compared to traditional approaches like error-prone PCR. The team began with a variant of rubisco isolated from semi-anaerobic bacteria, known as Gallionellaceae, which is one of the fastest rubisco enzymes found in nature. Through six rounds of directed evolution, they identified three mutations that enhance the enzyme's resistance to oxygen, thereby improving its preference for carbon dioxide.

The implications of this research are substantial. Shoulders notes, "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?" By addressing this question, the researchers are not only advancing the fundamental understanding of enzymatic processes but also paving the way for practical applications in agriculture. As plants are estimated to lose about 30% of the energy they capture through photorespiration, enhancing rubisco could lead to more efficient food production in the face of global population growth and climate change.

The findings of this study are published in the Proceedings of the National Academy of Sciences, reflecting the significance of this research within the scientific community. The potential applications extend beyond agriculture, implicating broader environmental impacts as improved photosynthesis could contribute to better carbon capture, thereby addressing climate change challenges.

In summary, the MIT team's innovative approach to enhancing rubisco efficiency marks a promising advancement in biotechnology and agricultural science. As they continue to explore the potential of this technique in various forms of rubisco, the future of crop yield improvement looks increasingly optimistic. With ongoing efforts to apply this research to plant-based rubisco, the agricultural sector may soon benefit from enhanced photosynthetic efficiency, ultimately contributing to food security and sustainability in an ever-changing global landscape.