Cyanobacteria have shown promise to produce citramalate, a key component for making sustainable plastics such as perspex.
The University of Manchester team says these photosynthetic microorganisms show the ability to convert CO2, a major greenhouse gas, into useful materials.
This research could significantly accelerate the creation of environmentally friendly alternatives to plastics, which are typically made from fossil fuel chemicals. Furthermore, it supports a circular bioeconomy, minimizing waste and reducing our environmental footprint for a more sustainable future.
23-fold increase in citramalate production
Cyanobacteria, also known as blue-green algaeare small organisms that use sunlight to convert CO2 into organic material. In particular, they offer a sustainable alternative to traditional methods by producing valuable products from CO2. They do this without the need for agricultural resources such as sugar or corn.
However, their slow growth and limited efficiency have hindered their widespread use in industry.
“Our research addresses one of the key bottlenecks in using cyanobacteria for sustainable production,” said Matthew Faulkner, the lead researcher.
“By optimizing how these organisms convert carbon into useful products, we have taken an important step toward making this technology commercially viable,” Faulkner added.
The research focused on Synechocystis sp. PCC 6803, a common cyanobacterial strain. They genetically modified the train to facilitate the conversion of carbon dioxide into bio-based materials.
This research aimed to improve the production of citramalate.
Citramalate is produced in one enzymatic step by combining two metabolites: pyruvate and acetyl-CoA. By carefully adjusting factors such as light intensity, CO2 levels and nutrient availability, the researchers achieved a substantial increase in citramalate production.
Citramalate production was increased 23 times by optimizing key process parameters, the study found.
Can be used to make materials other than plastics
Initially, the researchers produced only small amounts of citramalate.
Later they used a systematic ‘design of experiment’ approach to investigate how different factors interact.
This increased the production of citramalate. “As a result, they increased citramalate production to 6.35 grams per liter (g/L) in 2-liter photobioreactors, with a productivity of 1.59 g/L/day,” the researchers revealed in the press release.
The technique can also be used to make other environmentally friendly materials. This is because pyruvate and acetyl-CoA are also used to make many other important biomolecules.
Therefore, this method could be used in the production of materials for biofuels to pharmaceutical products.
The researchers emphasize that this development contributes to global efforts to combat this epidemic climate change and reduce our dependence on fossil fuels.
“This work underlines the importance of a circular bioeconomy,” says Matthew.
“By converting CO2 into something valuable, we don’t just reduce emissions – we create a sustainable cycle in which carbon becomes the building block for the products we use every day,” the author added.
They now want to further refine their techniques and investigate ways to efficiently increase production.
Furthermore, they are investigating how their optimization approach can be used for other metabolic pathways within cyanobacteria. This could help expand the range of sustainably produced biobased products.