Using evolution as a guiding principle, researchers have successfully engineered bacteria-yeast hybrids to perform photosynthetic carbon assimilation, generate cellular energy, and support yeast growth without traditional carbon feedstocks like glucose or glycerol. By engineering photosynthetic cyanobacteria to live symbiotically inside yeast cells, the bacteria-yeast hybrids can produce important hydrocarbons, paving new biotechnical pathways to non-petroleum-based energy, other synthetic biology applications, and the experimental study of evolution.
In previous studies, researchers had theorized that complex life forms began with the fusion of cells in a process called endosymbiosis. University of Illinois Urbana-Champaign chemistry professor Angad Mehta led a research team that showed lab-generated cyanobacteria-yeast chimeras can supply photosynthetically generated ATP to yeast cells but do not provide sugars. The team then engineered cyanobacteria to break down sugars and secrete glucose, creating chimeras that can grow in the presence of CO2, using the sugar and energy produced by the bacteria.
The study findings, published in the journal Nature Communications, illustrate the potential of engineering non-photosynthetic organisms into photosynthetic chimeras capable of producing valuable products like limonene, a simple hydrocarbon compound found in citrus fruits, under photosynthetic conditions. Mehta believes this proof-of-concept study demonstrates that pathways can be engineered in hybrids to photosynthetically produce limonene and other terpenoids, which are precursors to high-value compounds such as fuels and pharmaceuticals.
Mehta envisions a future where their method can recycle CO2 waste by assuring that every bit of carbon in high-value compounds comes from CO2. The team’s research goals include determining the feasibility of producing more complex compounds, like fuels and pharmaceuticals, using their engineered chimeras and scaling up the process for marketability. Through their work, they aim to advance biotechnology and answer fundamental evolutionary questions about the origin and development of life.
As the team continues to perfect endosymbiotic systems for biotechnological applications, they also aim to shed light on fundamental evolutionary questions. By recreating the evolution process in the lab, researchers hope to gain insights into how life evolved and how endosymbiotic systems can be engineered effectively. The interdisciplinary team of researchers at the University of Illinois includes Yang-le Gao, Jason Cournoyer, Bidhan De, Catherine Wallace, Alexander Ulanov, and Michael La Frano, supported by funding from the National Institutes of Health.
In conclusion, the successful engineering of bacteria-yeast hybrids for photosynthetic carbon assimilation represents a significant step towards sustainable biotechnological applications and the experimental study of evolution. By combining cyanobacteria with yeast cells to create chimeric organisms capable of producing valuable compounds like limonene under photosynthetic conditions, researchers have demonstrated the potential of this approach for producing fuels, pharmaceuticals, and other high-value compounds. Moving forward, the team aims to further explore the capabilities of their engineered chimeras and scale up the process for commercial viability, while also gaining insights into the evolutionary underpinnings of complex life forms through their research.