Cyanobacteria, also known as blue-green algae, have emerged as a promising tool in the development of sustainable plastics, such as Perspex, by producing citramalate—a key component in plastic production. Researchers from the University of Manchester have demonstrated that these photosynthetic microorganisms can convert CO2, a major greenhouse gas, into valuable materials. This breakthrough could accelerate the creation of eco-friendly plastic alternatives traditionally made from fossil fuel-derived chemicals, supporting the transition to a circular bioeconomy that reduces waste and carbon emissions.

Cyanobacteria are tiny organisms that harness sunlight to convert CO2 into organic matter, offering a sustainable method to produce valuable products without relying on agricultural resources like sugar or corn. Despite their potential, the slow growth and limited efficiency of cyanobacteria have hindered their large-scale industrial use.

“Our research addresses one of the key bottlenecks in using cyanobacteria for sustainable manufacturing,” said lead researcher Matthew Faulkner. “By optimizing how these organisms convert carbon into useful products, we’ve taken an important step toward making this technology commercially viable.”

The team focused on Synechocystis sp. PCC 6803, a widely studied strain of cyanobacteria, and genetically modified it to improve its ability to convert CO2 into bio-based materials. Specifically, they sought to enhance the production of citramalate, which is produced in a single enzymatic step by combining two metabolites: pyruvate and acetyl-CoA. By adjusting factors such as light intensity, CO2 levels, and nutrient availability, the team significantly boosted citramalate production.

Initially, citramalate production was low, but after employing a “design of experiment” approach, which systematically explored how various factors interacted, the team achieved a substantial increase. “We increased citramalate production to 6.35 grams per liter (g/L) in 2-liter photobioreactors, with a productivity rate of 1.59 g/L/day,” the researchers revealed.

This method could also be applied to the production of other eco-friendly materials, as pyruvate and acetyl-CoA are used in the synthesis of various important biomolecules. The researchers believe their technique could be used to create a wide range of sustainable products, from biofuels to pharmaceuticals.

Faulkner emphasized that this development contributes to global efforts to combat climate change and reduce reliance on fossil fuels. “This work underscores the importance of a circular bioeconomy,” he explained. “By turning CO2 into something valuable, we’re not just reducing emissions—we’re creating a sustainable cycle where carbon becomes the building block for the products we use every day.”

Moving forward, the team plans to further refine their techniques and explore ways to improve production efficiency. They are also investigating how their optimization approach could be applied to other metabolic pathways within cyanobacteria, potentially expanding the range of bio-based products that can be sustainably produced.

By Impact Lab